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Hi all,

I have a 2007 Mondeo Ghia 2.0 TDCi (140) on a 57 plate. Unfortunately I have had a medical issue and have spent sometime in hospital, well on the mend now though. Due to this however the car has been stood unused for sometime but was working perfectly beforehand. Now though, the 'Immobiliser Active' message is displayed and the car will not start/turnover. I have tried a number of things including leaving the battery disconnected over night and also ensuring it has been fully charged. Also locking/unlocking vehicle which I read may reset immobiliser. I have had the error codes diagnosed and get the following:

U0121 Lost communication with ABS module

U0129 Lost communication with Brake System Control module

U0415 Invalid data received from ABS module

U0416 Invalid data received from Vehicle Dynamics module

U0422 Invalid data received from Body Control Module

The diagnostic system is a Delphi one, the first two codes will delete but return, the last three codes will not delete.

I've checked the 5amp F36 fuse, which I think is the ABS one and removed and re-seated the relays in the engine bay fuse box. I have also read that there can be a problem with corrosion in the wiring loom from the fuse box area to the PCM but the picture of the wiring loom I saw looks a bit different from mine, so not 100% sure where to look, if indeed I would need to re the DTC's above. I thought it might be a possibility as two of the codes state lost communication, (also, while the test is being conducted a 'No system responded' message is displayed in the ABS section). If anyone can offer an insight into this problem I'd be most grateful as I understand it would need to be a Ford dealer/specialist that would fit and program a new ABS module and as I've not been able to return to work yet, funds are currently limited and if there is a way I can establish for certain, whether I need a new module or not would be extremely helpful. I.E; Could I run a test wire from the fuse box to the relevant wire on the ABS plug to establish communication. Where exactly would I need to check the wiring and if I did find a problem would the Delphi unit reset the codes it has found or would it have to be a Ford specific diagnostic unit?

Many thanks

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Hi Peter, Yes, definitely down to battery strength, which was good enough but not via jump leads, even with a booster/starter pack connected as well, which did surprise me. I had a similar readin

Hi again, Well, I did try to upload a 7 second video clip so you could share in my celebration :-). Car is starting on 1st turn of the key, so a big thank you to everyone for their input, it has

Well one way or another they are all communications problems or seem to be. 2 are lost communication 3 are are invalid data communicated. In this circumstance and particularly bearing in mind you

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Well one way or another they are all communications problems or seem to be. 2 are lost communication 3 are are invalid data communicated.

In this circumstance and particularly bearing in mind your history of non-use I would try:

- try removing the connectors from the modules give a spray of contact cleaner and wiggle around and re-try

- while you are there loo at the earths at the modules and if they appear corroded clean up and use contact cleaner

Faults after storage are often down to corrosion particularly if the car has been a little damp. Beyond that you might be well advised to try an auto electrician. I'm not sure that there is much argument for messing around with relays (the fault doesn't seem to be one of the relays) or the ABS module itself (it seems to be likely to be something to do with the CAN bus and inter-module communication rather than the ABS module unless it is the comms part of the ABS module with rather peculiar faults).
 

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6 hours ago, frenchspanner said:

Where exactly would I need to check the wiring and if I did find a problem would the Delphi unit reset the codes it has found or would it have to be a Ford specific diagnostic unit?

A CAN bus is just a pair of wires, usually twisted, that connects several electronic modules together. It conveys all sorts of digital messages between the modules, and causes massive problems if there is a fault on it.

The main CAN bus (HS-CAN) runs from the pcm (engine computer) to the IC (instrument cluster). It has spurs that connect it to other modules in between, including the ABS module. These spurs are usually wired to the main bus by splices hidden in the loom - not a good idea, but Ford PLC love it. They can fail, as can the connectors on the modules.

One helpful clue is that a CAN bus should measure 60ohms between the two wires when it is fully powered down. This is due to 120 ohm terminating resistors at both ends (PCM & IC). So this can tell you if the bus is intact. Also if the bus pins can be located on a module (eg ABS) connector, then this 60 ohms should appear between these two pins (on the loom connector), if the spur is connected to the main bus. The bus is also present on pins 6 & 14 on the diagnostic connector, which is an easy way to find the bus.

So if you can get at the ABS connector, ideally get a schematic (Haynes has some info, I do not have a Mondeo schematic), or look for twisted pairs, and buzz through from the pins to pins 6 & 14 on the diagnostic connector, to try to locate the CAN bus pins. (This would probably be best done after the earth & connector cleaning check suggested by BOF above.)

I think the Delphi can reset all the codes once the underlying fault is fixed.

I would try Forscan on the car, also. This is a free download, Ford specific system, and is about the best you can get apart from the Ford IDS system. It needs an adapter (ELM327) costing about £16, and a computer of some sort, Windows laptop is best.

What is missing is which module is raising the fault codes. It is odd that the Immobiliser is also affected. The Immobiliser (PATS) relies on the PCM & IC being able to communicate (Over the HS CAN bus). It looks like the fault may be on the main bus between these two. There may be additional error messages that Delphi is not seeing that would give further clues. Forscan might help here.

This may all sound a bit technical, but really it just comes down to tracking some wiring through the car, and checking resistances.

I posted a diagram of a Mondeo bus system in:

I can give more info on Forscan if you want.

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Hi,

Thank you very much for your replies. I had, or at least thought I had selected to be notified when I received a reply and was consequently waiting for an email to come through, not realising I had already received these responses.

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On ‎09‎/‎05‎/‎2017 at 0:27 AM, Tdci-Peter said:

What is missing is which module is raising the fault codes. It is odd that the Immobiliser is also affected. The Immobiliser (PATS) relies on the PCM & IC being able to communicate (Over the HS CAN bus). It looks like the fault may be on the main bus between these two.

 

Hi Peter, with regards to the above, I have read the following on a TalkFord post: "the ABS needs checking, on 2007 onwards Mondeo the ABS is part of the immobiliser system".

If it ever stops raining I will get out and check the items mentioned in yours and BOFs replies. I've checked one lot of earth connectors so far, (three together, back from the nearside headlight), I've removed the ABS plug and sprayed with Contact cleaner but the pins looked lovely clean and new looking anyway. I've also done the same for the plug at the ECU behind the nearside front bumper, (Is this the PCM, I'm guessing Engine Control Unit vs Powertrain Control Module? terminology difference). Did this 'blind' as could only partially remove plug due to anti tamper screw on casing.

With regards to pins 6 and 14, if I initially probe one with one wire from a DMM and the other with the other wire at the diagnostic socket and check for 60 ohms reading here first. If I do then the wiring should be ok but if I don't I need to then check through the loom?

Quote
On ‎09‎/‎05‎/‎2017 at 0:27 AM, Tdci-Peter said:

So if you can get at the ABS connector, ideally get a schematic (Haynes has some info, I do not have a Mondeo schematic), or look for twisted pairs, and buzz through from the pins to pins 6 & 14 on the diagnostic connector, to try to locate the CAN bus pins

Think I'm being a bit dumb, how do I buzz through? (Would I have one wire from DMM at say pin 6 at diag socket and then other wire from DMM to the twisted pair pins, (doing both pins one at a time and then repeat for pin 14 at the diag socket), again looking for 60 ohms and if I don't get 60 ohms on two of the four wire tests then there is a break in the loom somewhere)? Also check for 12v with ignition on?

Again, thank you for taking the time to respond and provide your valuable advice to my queries, it is much appreciated.

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2 hours ago, frenchspanner said:

With regards to pins 6 and 14, if I initially probe one with one wire from a DMM and the other with the other wire at the diagnostic socket and check for 60 ohms reading here first. If I do then the wiring should be ok but if I don't I need to then check through the loom?

Testing through car wiring is not very easy! The workshop manuals have long lists of check to do, but special pins are needed to go into the plugs, access to many plugs is quite hard, and they may be some distance apart. I doubt if many garages follow these checklists, they just replace parts or bits of wiring loom on suspicion, usually.

But the 60ohm test is an easy one, straight between the two pins (6 & 14) on the one connector. It does test the main bus from end to end, up to the terminating resistors on the PCM (yes, same as ECU) and IC pcbs. But it does not test right up to the ABS pcb, or to any of the other stubs on the bus.

Think of the CAN bus as a main highway from A to B, with short, dead ended side roads leading off it to various other intermediate destinations. It was a very silly idea doing it like that, but that is how it is.

However, if you do the same test from the ABS socket, you should still get the 60ohms reading across the bus, and that will show if the ABS socket is properly connected to the main bus. This assumes that you can locate the bus pins in the ABS connector. Trying all combinations looking for the 60ohms reading is one way, if you do not have a drawing (eg Haynes). I am 99% sure the two bus pins will be adjacent, or possibly opposite, to each other.

If that fails, then you need some sort of extension wire so you can test from the ABS connector back to the known bus pins on the diagnostic connector. If, for instance, you find one connection, but not the other, then that would indicate a broken wire in the stub to the ABS unit.

More likely is that the connections are poor, or intermittent. This will need some way to fix the DMM probes into the sockets while wiggling wires and connectors, and looking for resistance changes. Google "Backprobing" on one way to connect to car wiring, Unbent paper clips do work quite well in the diagnostic connector, and in some others, I have found. But take a bit of care not to overstress the connector terminals, or damage them.

You can not do much testing with the ignition on, unless you know what readings to expect, and where. The CAN bus does not work at 12v, it will be about 1v to 3v, I think, when powered up. Best to keep power off, maybe even battery -ve disconnected, while doing much work on the wiring. When working "live", extra precautions against short circuits and wrong connections are needed. Though some tests may have to be done live, to test sensors and stuff.

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Hi Peter,

Thanks for your reply, great information and has helped clarify things for me considerably. I will post back any findings when I have gone through the tests advised, I'll also try and track down the relevant wiring diagram.

 

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  • 2 weeks later...

Hello again,

Here is an update to my 'Immobiliser Active' issue. I have checked the diagnostic socket pins 6 & 14 and get a continuity beep and for resistance get a reading of 61.5 ohms, so the high speed Can Bus circuit test all seems ok there.

IMG_3148.thumb.JPG.117eefc4b8807228002b52e9eeeedc92.JPG

 

 

 

 

 

 

 

I have obtained a Haynes workshop manual for the MK4 Ford Mondeo (2007-2012) and although there are some wiring diagrams, there isn't one for the ABS system. However looking at the diagrams that are present, they are showing the H/S Can Bus twisted pair to be White/White & Blue, (every dia. showed same colours).

5929a591871f1_Mondeowiring.thumb.png.4a9b47e1c7dd0b9b4ce3bafe5a664fe9.png

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

I have peeled back the insulation on the wiring to ABS plug and also managed to unclip back of plug to establish which pins the wires go into.

Mondeo_Bus_wires.thumb.png.755c85b23fd9909b0e9dc167a57fe0d5.pngMondeo_BUS_ABS.thumb.png.3f9b638601e904a41909822b79763900.png

 

I put a couple of dressmaker pins in the relevant connectors and again checked the resistance measurement, which gave a reading of 61.7ohms.

Mondeo_ABS_pins.thumb.png.62fba0e3ec0c78998eca9de843d83075.png

Again, from what you have previously advised, I understand this reading suggests the H/S Can Bus wiring is all in order from the ECU/PCM via the ABS to the instrument cluster. 

I have been checking the wiring loom for damaged wires by removing the insulating tape and plastic sheath and where the loom passes by the bottom corner of the engine block I found a small damaged section where the loom must have been rubbing against the block as the engine vibrated during operation. Three of the wires had insulation partly rubbed through exposing the wires and it looked like corrosion had 'fused' the three wires together. This was looking quite hopeful as the culprit to my issue. I have separated the wires and cleaned off the corrosion as much as possible.

Damaged_wire_1.thumb.png.bc28c2eaa6538a3456f0d604a9b8be62.pngDamaged_wire_2.thumb.png.74efcd9c64e240781de603c28f5eb97c.pngDamaged_wire_3.thumb.png.11d4bb23bec79a1c0323400f03884e4b.png

 

The engine diagnostics was then re-run, (using the Delphi system) but the DTC's are exactly as before and the same three will not reset and the other two show as reset but return immediately ignition is turned back on. I have pushed a pin into the three wires either side of the area of damage and can confirm all of them have continuity and I could get a resistance reading to show on the DMM but it kept fluctuating for all three wires.

I really thought I had found the problem when I located the corroded wires but after separating them the issue persists.

Any further advice as always will be gratefully received.

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5 hours ago, frenchspanner said:

but the DTC's are exactly as before and the same three will not reset and the other two show as reset but return immediately ignition is turned back on.

Ugh. I know the feeling, when you find a real fault, but it does not cure the current problem!

I just re-read the 1st post, it is the last three that will not delete, I think you said. And that includes the BCM related error. I thought that a HS CAN bus problem could cause this, as the BCM messages have to use the HS-CAN bus to get to the pcm. But the BCM is always, as far as I know, on the MS-CAN bus. The junction point on the Focus is the IC (instrument cluster), but on the Mondeo, the only diagram I have seen shows the A/C unit (!) as the junction. This is where messages can pass between the two busses.

If the BCM fault is permanent and recurring, it widens the search a bit, to the MS-CAN bus. This is on pins 3 & 11 of the diagnostic connector, and can be resistance tested in the same way (60 ohms).

One way to test if the ABS module is working, is to run a self test on it. I am fairly sure that Forscan can activate an ABS test routine on my Focus. The only sure way to find out if it can do this on your car is to get an ELM237 lead & download Forscan to try it. The test will use the HS-CAN bus between the diagnostic connector & the ABS unit, so would check that out.

If you get a "modified" ELM, Forscan can also directly access the BCM, and I think do a self test on that.

This sort of problems can be a real pig. But that is the best I can think of at the moment.

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Hi Peter,

Thanks for your reply, yes using the Delphi diagnostic the five codes listed are 'picked' up. When selecting 'Erase DTCs' the U0121 Lost communication with ABS module and U0129 Lost communication with Brake System Control module change from red to green and then are removed from the DTC summary on main screen. U0415 Invalid data received from ABS module, U0416 Invalid data received from Vehicle Dynamics module & U0422 Invalid data received from Body Control Module when selected for 'Erase' stay red and then show with a red line through them instead of turning green and remain on the main summary screen. If the diagnostics is run again all five DTCs show up as before. 

I will get on with the points you suggest and report back with my findings. You mentioned the junction point for the MS CAN bus on the Mondeo shows the A/C unit, would that mean the compressor in the engine bay or the A/C controls in dashboard console? The MS CAN bus twisted pair are showing as violet & orange/ grey & orange in the Haynes manual and they aren't present at the ABS plug, (There are four more twisted pairs in addition to the HS CAN bus, which I am guessing go to the relevant wheel sensor). So maybe the message isn't getting to the ABS module from the Body Control Module, (as it should transfer from the MS CAN to the HS CAN at the junction point at the A/C unit,  if I'm understanding you correctly? Haynes don't seem to mention a Body Control Module but do list a GEM, Generic Control Module which is integral to the passenger compartment fuse box and states that one of the things it's responsible for is the management of the Anti-theft system. Is the GEM the BCM?

One other point; I've been assuming all along my key is working properly because if there was a fault with it causing the 'Immobiliser Active' message, I would be getting different DTCs to the ones I have.      

Thanks again

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8 hours ago, frenchspanner said:

the junction point for the MS CAN bus on the Mondeo shows the A/C unit, would that mean the compressor in the engine bay or the A/C controls in dashboard console? The MS CAN bus twisted pair are showing as violet & orange/ grey & orange in the Haynes manual and they aren't present at the ABS plug, (There are four more twisted pairs in addition to the HS CAN bus, which I am guessing go to the relevant wheel sensor). So maybe the message isn't getting to the ABS module from the Body Control Module, (as it should transfer from the MS CAN to the HS CAN at the junction point at the A/C unit,  if I'm understanding you correctly? Haynes don't seem to mention a Body Control Module but do list a GEM,

I guess some sort of climate control unit is standard on the Mondeo, and it will be this electronic module that would be the junction point. It will be behind, or near, the a/c & heater controls. But that is from one source, fordwiki.co.uk, and it does seem odd to make this module the junction. The IC is a much more logical cross-over point.

MS-CAN does not go to critical underbonnet modules like ABS, only the HS_CAN does. GEM is a Ford term for BCM. Just like PCM is a Ford term for ECU.

That U0422 DTC does suggest that locating and checking this MS/HS CAN bus link might be relevant.

Good point about the keys. Does the car have a PATS (immobiliser) LED? There are PATS flash codes that indicate the cause of immobiliser problems, common to most Fords. After a period of steady flashing, it sends a code as quick flashes with gaps,  Example - 1 flash -PAUSE - 6 flashes = flash code 16.

16 is a (CAN bus) communication error, 13 to 15 relate to Key problems, or possibly to PATS sensor unit problems.

Google PATS flash codes for more info.

The lack of key or PATS related DTCs also suggests it is not a key or PATS sensor problem. However, PATS can be a bit peculiar, and the vagaries of modern software never cease to amaze and horrify me wacko.png, so it is not possible to really rule out anything!

.

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Thank you Peter.

The GEM is part of the passenger fuse box, so I will look for the MS CAN bus twisted pair there and check resistance and then try to follow it up to the A/C unit and look for a junction with the twisted pair of the H/S CAN bus and check the connection. 

I'm not sure about the anti-theft system, I don't know if it's a PATS system with the LED, it may have been updated when the ABS was incorporated into the immobiliser circuit. I'll reconnect the battery and look for a red light, it's not between the instrument dials like previous models but might be one on top of dashboard, (memory is letting me down there!).

I'm about to order a Forscan modified ELM327 that is UK stock item and is advised to contain a genuine 25K80 chip with 500k connection and use genuine Silicon Labs USB chips. £15.90 inc. del. ( http://www.ebay.co.uk/itm/New-Modified-ELM327-USB-Ford-Elmconfig-Focccus-Forscan-Focus-Smax-Mondeo-Kuga-/222507981410?hash=item33ce825a62:g:6XgAAOSwGIRXZT2v ). I think that is probably as good as any other, unless you would recommend otherwise. Where would be the best place to obtain/download the relevant software?

Thank you and regards,

Keith

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4 hours ago, frenchspanner said:

Where would be the best place to obtain/download the relevant software?

Steve Elmer on Ebay is the same as the Tunnelrat Electronics ref. below, I believe. You get full Ebay protection if you get it that way.

-----

Forscan is a powerful Ford specific system, Cost is about £15.00 for the interface. It needs a computer of some sort. (COM port, USB, bluetooth or WiFi interfaces available). You will find a lot about ELM327 & Forscan on this site, which together provide a very comprehensive diagnosis & maintenance tool. James (jeebowhite) has done a nice guide: http://www.fordownersclub.com/forums/applications/core/interface/file/attachment.php?id=21196

The Tunnelrat ELM237s have been reported to work well by several people, and are stated to be compatible with Forscan and ELMConfig.

http://www.spanglefish.com/TunnelratElectronics/index.asp?pageid=516992

Forscan works best on a Windows laptop, with a USB ELM.  Forscan is also available for iOS & Android for some tablets & phones, using USB if available, or bluetooth or WiFi ELMs.

Wireless ELMs are often not as reliable as the wired ones. Also they are rarer in the "modified" form which is needed to access the 2nd Ford bus system. This 2nd bus is the MS-CAN bus, and links all the car interior electronics like door modules, and the BCM (aka GEM). But a standard ELM will still work with all the Underbonnet Modules (PCM, ABS etc) and with the IC (Instrument Cluster).

The Forscan programme is free (in Windows format) and you can get it from:
http://forscan.org/download.html

 

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  • 2 weeks later...

Hello again,

I've now purchased and received the ELM237 unit and downloaded the Forscan software. After running the diagnostic on the car, I get the following:

DTC's in PCM;   PO1113P  Intake air temperature sensor high input - (Probably due to removing air cleaner to access loom).

                          UO129 (:00-2F)  Lost communication with Brake System Control module

DTC's in BCMii; UO121 (:00-2F)  Lost communication with ABS module

                          UO199  Lost communication with Door Control Module  (There is a break in the wire to the drivers door somewhere that stops electric window etc. working, only present if door is open. Has been present for a long time and long before current issue).

DTC's in IPC;    UO422 (:68-2B)  Invalid data received from Body Control Module  

                         UO415 (:68-2B)  Invalid data received from ABS module

                         UO416 (:68-2B)  Invalid data received from Vehicle Dynamics module

                         UO199 (:00-2B)  Lost communication with Door Control Module

I have removed the Aircon control panel and there are two plugs with a plethora of wires going to them, including a twisted pair which I think is the MS-CAN bus. These are Violet/Orange & Grey/Orange.

 

IMG_3264.thumb.JPG.f727829939676ec865da217009b35bf6.JPGMS-CAN_bus_air_con.thumb.png.21282b1bdf2f2fb0afb2df19e59257fc.pngMS-CAN_bus_air_con_1.thumb.png.939e8ca4e05c1b69ae92dc4ab14f4dab.pngMS-CAN_bus.thumb.png.51db4bab6ebaebcfb8c483640c5c1b9f.png

The reading I got with a DMM between these two wires was 66 ohms, so I guess ok.

I then unclipped the Passenger fuse box/GEM and removed the plugs and had a look at the wires on each, I came across another Violet/Orange & Grey/Orange twisted pair on one of the plugs, (the grey was a darker shade and the Violet was a lighter shade than the pair at the Aircon unit so I may not have the correct wires at one or the other or both but I couldn't find another twisted pair that matched the MS-CAN bus colours).

MS-CAN_bus_GEM.thumb.png.ac783690bdbeb9679dd9adf029036120.pngIMG_3288.thumb.JPG.80a31890a86f8dd76bba59703518290a.JPGIMG_3287.thumb.JPG.e52354408397bb1467ee7a7f85c1641b.JPG

The DMM reading I got for these was 121.2 ohms, (does this indicate a problem). The wires from this socket go up into the foot well and then out through the bulkhead to the engine bay. It is a big, thick loom with a lot of wires, it separates after coming out of the bulkhead with the larger part running along the passenger inner wing towards the fuse box and the smaller branch running across the rear of the bulkhead towards the drivers side. I have stripped some of the insulation from the larger branch but haven't located the twisted pair in question, there are a lot of wires, so they may be buried and I haven't managed to expose them yet or they are in the smaller branch which is very difficult to access.

I have been looking for a suitable wiring diagram that shows the routing of the MS-CAN bus twisted pair but have had no joy at all.

If any of the above information has shed some more light on the situation, as always I would be very grateful for any advice.

Many thanks,

Keith

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1 hour ago, frenchspanner said:

DTC's in IPC;    UO422 (:68-2B)  Invalid data received from Body Control Module  

                         UO415 (:68-2B)  Invalid data received from ABS module

                         UO416 (:68-2B)  Invalid data received from Vehicle Dynamics module

                         UO199 (:00-2B)  Lost communication with Door Control Module

It looks to me like it is the IPC (Instrument Panel Cluster) that is the Bus gateway on this car. I suspect the drawing showing the A/C module as the gateway was an earlier version. It is more logical and consistent with other Fords to use the IPC.

I think two of the above errors are on the MS-CAN bus (Door & BCM), and two are on the HS-CAN bus (ABS & VDM). That puts some wort of problem inside the IPC as a likely cause. It also suggests that the MS-CAN bus does go to the IPC.

 

1 hour ago, frenchspanner said:

The DMM reading I got for these was 121.2 ohms, (does this indicate a problem)

Was the 121 ohms with the BCM connector un-plugged? If so, it is correct, as one of the 120 ohm terminating resistors will be inside the BCM, and hence disconnected, and you will only measure the one at the other end. You could try probing the relevant (MS-CAN bus) socket pins on the BCM to test for the 120 ohm resistor in there.

With 3 different modules showing errors in the IPC, if the MS-CAN bus wiring checks out ok, then suspicion transfers to the IPC. Maybe a problem inside the ABS could cause the VDM & BCM errors, but I do not see, logically, how. Unfortunately, these systems are not always logical, at least not until the full story including software, is understood!

Have you looked in Forscan for the self-test functions: It should be able to test the ABS, IPC (or IC), and BCM. It might give some added clue.

Also the Instrument Cluster usually has a number of fuses supplying power to it, 3 I think on the Focus. One of these being gone could have odd symptoms.

 

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Knowing the Focus IC problem with damaged/broken solder joints on the IC connector, have we checked the security and condition of the connector / solder joints on the back of the IC?

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Hi,

Thank you for your replies, yes the 121.2 ohm measurement was with the plugs removed from the GEM/BCM. I will check if I can get access to recheck the measurement with the plug in situ. (The previous HS-CAN reading of 61.7 ohms I got from ABS plug was with it unplugged also). I also forgot to confirm that I tested pins 3 & 11 on the diagnostic socket before the ELM237 came and got a reading of 61 ohms.

I re-ran the diagnostic scan and I'm pretty sure there were no IPC errors listed on computer screen until the Forscan prompted for the ELM237 unit to be switched from HS to MS mode and OK pressed to continue. I also think the BCMii didn't list fault codes until after switching to MS mode either but would have to check this to confirm. The program runs pretty quickly and I'm just getting to grips with its operation.

I have had a look around Forscan and couldn't find the ABS module listed anywhere to carry out a specific test on it. I found a screen with numerous modules listed but ABS was absent.

While I had good access to it, I checked all of the fuses in the passenger fuse box and they were ok. (I've just checked and F8 is a 5A fuse for Instrument Cluster). F41 is a 10A fuse in Engine fuse box for IC, I will check that too. I can't see any others listed.  

 

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19 hours ago, frenchspanner said:

the 121.2 ohm measurement was with the plugs removed from the GEM/BCM. I will check if I can get access to recheck the measurement with the plug in situ. (The previous HS-CAN reading of 61.7 ohms I got from ABS plug was with it unplugged also). I also forgot to confirm that I tested pins 3 & 11 on the diagnostic socket before the ELM237 came and got a reading of 61 ohms.

That all makes sense. The ABS will not have a terminating resistor in it, it is not at the end of the bus, but in the middle. The terminating resistors for the HS CAN bus will be in the PCM (aks ECU or ECM), and in the IPC. So it will still read 60ohms when disconnected. The BCM has an MS-CAN bus terminating resistor. I am still not 100% certain of the other end of the MS-CAN bus, but the IPC looks to be the most likely. Though that Fordwiki drawing shows it as being the A/C unit.

But the both buses look intact, as far as the wiring goes, from your tests so far. It does not seem to be an intermittent fault as it always comes back immediately. There is a complete lack of any error codes or information relating to PATS or immobiliser or keys. That suggests it is not just a key recognition error.

It is looking more like an electronic unit fault. Top suspect is the IPC, as the ABS module can not really cause the BCM related error in the IPC, it is not on that bus.

Ted's suggestion (Micro) is a good one. The Focus IC is notorious, and I have heard quite a few complaints about the Fiesta one. I know little about the Mondeo one. Like how easy it is to get at or test.

But if it was a bad connection on the bus, and if the IPC does contain the terminating resistor, then that would show up on the resistance tests. That is how I located a fault in my IC. Disconnecting the A/C control module and repeating the 3-11 test at the DLC would tell you if the resistor was in that module.

It is a shame if it is a faulty module. If it is not obvious, like a visible bad joint, then it will either be go to a Ford dealer sad.png, they will probably start swapping modules at great expense. Or take a risk to have a suspect module sent away for repair. They may not find the fault, or it may not be the faulty unit. But there are some fairly good repair services available.

Clive (Stoney871) recommends:

http://www.clusterrepairsuk.co.uk/repair/make/ford

----

Hmmm - I have just noticed in the photo of the Haynes manual page above, that the HS CAN bus also goes to the BCM, as well as the MS CAN bus. This somewhat damages my logic about the ABS not causing BCM errors. It is not possible to say for sure which bus is in use when the BCM to IPC invalid data error happens. It makes narrowing this problem down to one module, or one bus, rather harder! Yuk. The Forscan results still point to IPC as a strong suspect, though.

Maybe you could try starting the car with the ABS fully disconnected. See if the error messages change.

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Hi,

As a bit of an update; With the plug removed the corresponding MS-CAN bus pins on the GEM/BCM unit gave a reading of 124 ohms, so that seems to check out ok. I've had another session with the Forscan and took some screenshots as follows;

DTC scan result in HS-CAN mode:

Diagnostic_MS-CAN.thumb.png.29f914027fc9c5bf20292f35709df11a.png

 

 

 

 

 

 

 

 

 

 

 

DTC scan result after switching to MS-CAN mode:

Diagnostic_MS-CAN_1.thumb.png.35daf5cfb10f6e11facb344ba7ad4d73.png

List of Modules:

List_of_Modules.thumb.png.dc4e358691bae3d68e26c01d00e51f7e.png

Self test screen:

Self_Test.thumb.png.0ec458dd3d6f3a37783af687f2d3cf43.png

No ABS listed. PCM test just advised P0113 Temperature sensor due air cleaner removed:

593c2f0f6b768_PCMselftest.thumb.png.02fa4f13ce79885019d9439ec2e7345d.png

IPC test came back clear:

593c2fc39aebc_IPCtest.thumb.png.b8a46493d5b3f387ed668a43ee31b2b5.png

The BCMii test would not complete and I keep getting the following message:

593c30c36bc98_BCMiitest.thumb.png.b788f2b8263d67ab32f46b7f629c5bc6.png

The OBD II mode 6 test detected a malfunction but didn't give further info:

593c32cad08cf_OBDIItest.thumb.png.0e376d97f79a5a7724531651a977a6d9.png

 

 

 

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Hi Peter thanks for your post, I was typing the above and putting on some graphics when it came through and didn't notice it until I submitted reply. The IPC self test came back clear so I don't know if there could still be a problem there. I had thought about resistance testing the HS-CAN pins on the ABS unit itself, if I can get to them but as there is no terminating resistor would I expect to see a specific reading or nothing when it's disconnected and no power to it?

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4 minutes ago, frenchspanner said:

List of Modules:

Clank.

All change!

It is the BCM.

The BCM is the key gateway on both buses, not the IPC, not the A/C.

It fails its test.

All messages from MS to HS busses have to pass through this module.

Forscan can be a very informative tool.

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Thank you Peter. Does it mean that there is a fault with the unit or a connection issue including a bad earth to unit or any of those? I have had the unit completely disconnected looking for the MS-CAN twisted pair and reconnected the plugs, so they are definitely properly seated and look clean. I've also checked all the fuses as the passenger fuse box is part of the same unit as the GEM/BCM. (I put it this way just to clarify to myself I'm not talking about the Brake system Control Module, (which I don't know it's location unless it's part of the ABS unit). 

So, to clarify in my mind, even though both the CAN busses seem to check out as intact, the information stream is failing at the GEM/BCM and that is why the ABS module doesn't seem to exist, even though it maybe is being communicated with but the information isn't making it's way back to the IPC on the MS-CAN due to a failure at the GEM/BCM to transfer the info from the HS-CAN to the MS-CAN? Shouldn't the ABS module at least show up on the HS-CAN test though, with a DTC code or two?

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2 hours ago, frenchspanner said:

Shouldn't the ABS module at least show up on the HS-CAN test though, with a DTC code or two?

You are right, I think!

I was called for dinner, so did not have time to look long enough to (not) see the missing ABS on the HS-CAN bus. I guess Forscan will only display info about modules it can actually find. It uses the CAN buses, directly from the DLC. So something is stopping it getting any answer from the ABS.

It must be there really, as the PCM & BCM both try to talk to it. But also fail. Also you have seen & tested the HS-CAN bus wires at the ABS connector. It does look like the ABS is dead, at least as far as comms go. I guess you have checked any ABS fuses. That lack of wiring diagram info for it is a pain, it would be possible to check for a 12v supply if we knew what pin it was.

But the BCM looks to have a fault also. The IPC can not get data from the BCM, and that would be via the MS-CAN bus. Also the BCM does not seem to want to do its self test. Forscan finds the BCM, but that that was via the HS CAN bus, so there could be a fault in the BCM on the MS CAN bus section. It hard to find a good link between a failed ABS and this odd BCM problem. Unless it is some odd software thing.

The IPC can not any data from the ABS or VDM either. The VDM is also known as ESP, I think, and gets data from the steering angle sensor (SASM) and a yaw rate sensor to activate the ABS to control spins & cornering skids. I suspect it is built into the ABS, so is only a virtual module, using the same physical connections. In earlier cars it was a separate, add-on module. VDM also does not appear in the Forscan list of modules. In the Mk2 Focus, the ESP is built in to the ABS unit.

I would also guess that Brake system Control Module is an overall term for ABS & VDM, used in the PCM. That would make sense with the error lists.

So the complete lack of any communication with ABS, VDM or BSCM does put that unit (the ABS physical unit) at the top of the list again, with the BCM coming second. I do wonder if that damaged cable may have damaged the ABS, or if there is still a cable fault there, as water getting into cables can cause internal corrosion, leading to conductor breaks hidden inside the insulation. Finding the 12v supply and earth connections for the ABS would be useful.

If you measure across the CAN bus lines of a module which is not a terminating one (so it has no 120 ohm resistor), then I think you will see a high resistance, or open circuit. CAN bus transceiver inputs are specified to a high level of toughness, able to withstand voltages of more than the battery voltage in either direction.

 

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Thanks Peter. Yes, I've been thinking about those three wires I found, I did check for continuity by placing a pin an inch or so either side of the damage and got a continuity buzzer for each wire. I guess even though each wire isn't completely broken maybe it's enough to restrict the required current. I was reluctant to start cutting wires because the car parking for the houses is remote to my house and I can't get power to the cars location, so soldering is an issue. I think I will 'splice' a piece of wire to bypass the damage, without actually cutting through the existing cable, using the dreaded blue Scotch-lock connectors, at least they should be good enough to test.

Yes, a decent wiring diagram would be a godsend, but I've so far exhausted the ways I've thought of searching for one. At least it looks like it is narrowed down to the ABS module, the GEM/BCM module or maybe a power supply/earth fault to one or the other as from what I've managed to test, the two busses look to be intact.

I have previously tried to start car with the ABS module unplugged but didn't help. If I was to bridge the HS-CAN bus wires in the ABS plug would that make a difference or is it a no, no to do that sort of thing.

Thanks again for all of your input and also to the other contributors, it has been much appreciated. If nothing else, I've learnt quite a lot about things I hadn't much of a clue about beforehand.

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3 minutes ago, frenchspanner said:

If I was to bridge the HS-CAN bus wires in the ABS plug would that make a difference or is it a no, no

All the devices on a CAN bus are in parallel across the bus. So all the CAN+ pins are wired together, and all the CAN- pins are wired together. A short circuit between these lines will stop any communication on that bus. Though it should do no long term harm, as I said, the transceivers are designed to survive short circuits & funny voltages.

I was hoping it was a bus wire fault, as they a relatively easy to locate. Power and earth problems are harder, especially without decent wiring info. If you bought a Focus, the full wiring diagrams for the Mk2 & Mk3 are on this site. But I can not find anything for other models. Ford ETIS has them, but it gives them in bits & pieces, it can be hard work to get much info. And you need dealer level access. Which I do not have!

Water can penetrate a long way inside cables, and cause problems some distance from the entry point. For this problem, I doubt if a bit of added cable resistance will have any effect, the ABS should not need much current to just power up and communicate. It would take a complete break, or a short circuit, to have the effect you see, I think. An faulty earth wire might have a bit more effect, but the CAN bus system is designed to tolerate offset voltages caused by currents flowing in earth lines.

I have learnt a bit too, I did not know the BCM was used as the gateway. That could be useful in the future.

I have just been looking at the TJA1050 High Speed CAN transceiver data sheet (as you do wacko.png). I have to revise my last post a little, it says the differential input resistance (ie measured between the lines) for a transceiver is 50k ohm typ (25k to 75k). So that should be what you would see on the ABS unit between the CAN bus lines when disconnected.

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