Immobiliser Active

[frenchspanner]

Hello again,

A delayed update as I have been away for a little while:

I checked the resistance between the CAN bus lines and got around 44k ohm, so that seems to agree with your revised info Peter. I have gone through every wire on the ABS plug and checked for voltage with ignition on and off. Pins 1 (Rd/Ye) & 25 (Rd) = battery voltage, ign. off or on. Pins 5 & 6 (H/S CAN) 2.7v & 2.4 respectively ign. on. Pin 33 (Gy) battery voltage ign. on. Pin 7 (Gn/Rd) 0.3v ign. on or off. As the Can bus has checked out ok and the unit seems to have power, I reluctantly acknowledged that a new ABS module is required.

However, just a few minutes ago, I actually managed to find some diagnostic info re Mondeo Mk4 ABS..................

DTC Table -. C12900 No communication with the anti-block brake system module. GO to Pinpoint Test AB.

I got U0129 but I guess this must be the same.

Pinpoint test AB.......

http://workshop-manuals.com/ford/mondeo_2007.5_02.2007/mechanical_repairs/4_electrical/418_electrical_distribution/418-00_module_communications_network/description_and_operation/diagnosis_and_testing/communications_network/#G927145p29

AB23: CHECK THE VOLTAGE AT THE ESP MODULE 1 Measure the voltage between the ESP module, connector C1CA01, pin 7, circuit SBB36A (GN/RD), wiring harness side and ground. Is battery voltage measured? Yes GO to AB25. No GO to AB24.

(No voltage was about 0.3v slightly less with ign. on).

AB24: CHECK FOR OPEN CIRCUIT BETWEEN THE EJB AND THE ESP MODULE 1 Disconnect Connector C1BB01-A from the EJB. 2 Measure the resistance between the EJB, connector C1BB01-A, pin 41, circuit SBB36AB (GN/RD), wiring harness side and the ESP module, connector C1CA01, pin 7, circuit SBB36A (GN/RD), wiring harness side. Is a resistance of less than 2 Ohms measured? Yes CHECK and if necessary RENEW the EJB. CHECK system operates correctly No LOCATE and REPAIR the break in the circuit between the electronic stability program module and the EJB using the Wiring Diagrams. CHECK system operates correctly.

I'm assuming the EJB is engine bay fuse box, I've just got to try and identify pin 41 at the correct connector and check resistance.

A question I have is; To test, would I be ok to provide a temporary battery voltage supply to pin 7 at the ABS plug and see if car will start or could that cause a problem. I'm thinking it would be ok because I looks like it should be a permanent live, ignition on or off. I will try to trace the red/green wire from pin 7 first but if its a bit awkward, I had thought of doing that as I've got a bit excited there may be a glimmer of hope that it is actually a wiring issue and the suspect wire has been located.

As always, many thanks for any contributions to this topic.

[frenchspanner]

Well, some good news.

I have traced the Rd/Gn wire from the ABS plug and it travels up to a plug mounted at the top of the bulkhead just under the windscreen. after disconnecting the plug, I checked the voltage from the EJB to the plug and the voltage was about 0.6v, so after removing even more insulation, I traced the wire back from the plug and found a 'lump' in the wire...

 

                                                 

 

 

 

 

Checked voltage either side..

    .

 

 

I've cut out 'lump' and temporarily twisted wires together and tried to start.......No 'Immobiliser Active' message and car turned over immediately. I reconnected scanner cleared DTCs and rescanned, just the IAT sensor one, so plugged air cleaner connector back in and retried. All codes clear :-) ...

 

The only thing is, is the car won't fire up! I don't know if it's because it's been stood for so long but it's just turning over, no hint of spluttering to life. I have noticed that the green dashboard direction indicators are flashing intermittently as it turns over. Does this mean anything in particular? All DTCs are still clear after cranking, there is diesel in the feed pipe at the engine and I couldn't see an airlock.

 

[Stoney871]

Could be something simple like the battery needs a charge.
Check the voltage at the lighter socket, you should have at least 12.4v on ignition.
Diesels need a fair bit of power to crank over effectively.

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[frenchspanner]

Thank you Stoney, I haven't checked via cigarette lighter socket but just checked battery directly, (been stood for couple of hours, not connected to car). Getting a reading of 12.78 volts.

[Stoney871]

Direct battery reading should be 14v plus so wouldn't hurt to give it a charge or a boost and see how you go.
Btw, great bit of persistence in locating your wiring fault.
Many would have wrapped their hand in by now.

Sent from my SM-G930F using Tapatalk

[frenchspanner]

Thank you Stoney, I thought it was anything over 12.6v is ok, I will put it on charge now and give it a another try tomorrow. Yes, I'm really glad I stuck with it, (even though it was more a case of needs must and I couldn't bare the thought or the cost of taking it to a Ford dealer). I was really chuffed when I found it, all codes cleared and it turned over. Just took the shine off it a little bit when it wouldn't fire, but hopefully something simple.

[Jonro2009]

Interesting reading, confusing but interesting. You are a better man than I am, I would have given up shortly after I started writing about the problem lol


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[Tdci-Peter]

On 23/06/2017 at 7:31 PM, frenchspanner said:

I thought it was anything over 12.6v is ok, I will put it on charge now and give it a another try tomorrow.

Over 14v is on charge, via a charger or with the engine running. 12.6 is not bad for a battery that has been standing, but it is hard to be sure, the voltage is not the full story. So it is worth trying a bit of charge, faster cranking may result, that could get the fuel in, or the compression up.

I have been distracted on other jobs a lot lately, so missed the excitement of finding a fault, and clearing the codes. Great work, but I know all too well the "Monty Python boot" feeling as you fix one thing, only to find another problem!

Forscan can read fuel rail pressure & cranking rpm while trying to start. I have done it, and can dig up some details if it would be useful.

A diesel only needs fuel & compression to go, so one of those must be missing!

 

[frenchspanner]

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 all been helpful but especially to Peter for all the time he has taken to provide the advice and information he has, thank you.

Hopefully to save anyone else inadvertently doing what I did, here's what happened today: I bled the system from the diesel return pipe and some air did come out but there was still a bubble on the feed side of the pump that just would not pull through with the hand bleed pump I used, (proper Draper fuel bleed tool). The car still wouldn't start. The battery has been charged up and was, I thought cranking ok. (I tried live data on Forscan but as soon as I started cranking an error message kept coming up on screen). Due to the fact the battery tray has been removed to get access to wiring loom, I had battery connected via jump leads with an additional car starter/booster pack attached for some extra juice and as I say I thought car was cranking pretty well. Before I packed up for the afternoon to have a good sulk, I balanced the battery as best as I could in the car and connected it directly.................................... started first turn of the key!! Lesson learned!

Thanks and regards, Keith

(N.B. I've got 'Notify me of replies' ticked but I never get a notification, do I need to do something else? It's just that if anyone else has 'Immobiliser active' message and wants to know exact location of problem wire I had, I won't know they have asked the question if they add it to this topic).

[pragmatix]

Well done glad you got it sorted

[Tdci-Peter]

5 hours ago, frenchspanner said:

I had battery connected via jump leads with an additional car starter/booster pack attached for some extra juice and as I say I thought car was cranking pretty well. Before I packed up for the afternoon to have a good sulk, I balanced the battery as best as I could in the car and connected it directly.................................... started first turn of the key!!

Great news!

It makes a nice change to hear a successful result. So often threads just go dead.

The cranking speed on these diesels is really quite critical, I suspect it needs 200 rpm before the injectors even try to put any fuel in, and 200Bar on the rail also.

I have tried starting a diesel by hand, a single cylinder cement mixer!. But the compression is incredible, you have to use a valve lifter, build up speed and drop the lifter, whack it hard over the first compression, aided by the massive flywheel, then it will fire up. This just illustrates the job that the battery and stater motor do. Even a little bit of added resistance in the cables may drop the speed below the critical threshold.

The Forscan data below is from my 1.8 Focus (Not the cement mixer, though some people would put the two in the same category)

From:

 

[frenchspanner]

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 reading on Forscan until I went to crank, which is when an error message came up, so may well have been due to connection via jump leads, will have another go when I've finished re-taping the looms and putting the bits back.

The Focus is a cracking car, I had the original shape one with 10,000 miles on it, a 2001 model and was really impressed with it, great handling and I found it really enjoyable to drive. My sister had it off me in 2009 and it's still going strong now, 130,000 miles later, It has never let either of us down, probably last year for it as corrosion is starting to take hold underneath and the welding required would be in an inaccessible area if needed for next MOT. I also think the latest shape one is a really attractive car as well.

Thanks again for your advice and assistance.

 

[Micro]

On 2017-6-23 at 7:31 PM, frenchspanner said:

Thank you Stoney, I thought it was anything over 12.6v is ok, I will put it on charge now and give it a another try tomorrow. Yes, I'm really glad I stuck with it, (even though it was more a case of needs must and I couldn't bare the thought or the cost of taking it to a Ford dealer). I was really chuffed when I found it, all codes cleared and it turned over. Just took the shine off it a little bit when it wouldn't fire, but hopefully something simple.

Car batteries (really any chemistry) can creep up in voltage when no current is flowing. As soon as you draw power, the voltage will drop to a point that it is unable to supply the required power.

Short circuits on the canbus network do not cause any long term harm apparently, as I managed to short them whilst fiddling (just shows up with a "Systems error"/"Engine Fault" or such in the info display).

Congrats on fixing it!

[Trillionz]

What a good read that was well done all I have Delphi but will be sorting myself a copy of Forscan now thanks!.

[waynes had enough with it]

On 7/25/2017 at 4:58 PM, Trillionz said:

What a good read that was well done all I have Delphi but will be sorting myself a copy of Forscan now thanks!.

hi everyone 

help i have got a similar fault i have found on obd plug pins 6-14 i have 133 oms

car wont start brake module has been tested all ok no faults 

it must be a wiring fault somewhere pcm wake up signal    B10E5    

most of the modules say error 

can anyone addvise

[Tdci-Peter]

2 hours ago, waynes had enough with it said:

i have found on obd plug pins 6-14 i have 133 oms

That indicates a break in the main (HS) CAN bus.

Try bashing the fascia near the instrument panel, and if you can locate any of the connectors, give those a good wiggle to see if the reading changes.

You need to locate the connectors on the CAN bus. On the Focus there is one in the engine bay fuse box, linking many of the PCM circuits to the rest of the car. There may be something like that on the Mondeo, and there must be one somewhere near the front bulkhead, this is needed during vehicle assembly. Or remove the instrument cluster to disconnect that. Unfortunately I do not have a wiring diagram for the Mondeo, and this is almost essential to trace an open circuit in the bus.

 

[waynes had enough with it]

10 hours ago, Tdci-Peter said:

That indicates a break in the main (HS) CAN bus.

Try bashing the fascia near the instrument panel, and if you can locate any of the connectors, give those a good wiggle to see if the reading changes.

You need to locate the connectors on the CAN bus. On the Focus there is one in the engine bay fuse box, linking many of the PCM circuits to the rest of the car. There may be something like that on the Mondeo, and there must be one somewhere near the front bulkhead, this is needed during vehicle assembly. Or remove the instrument cluster to disconnect that. Unfortunately I do not have a wiring diagram for the Mondeo, and this is almost essential to trace an open circuit in the bus.

 

Hi Peter thanks for the reply 

when I get a chance I will take a look 

the fault is on the ms side

but the abs is on the hs side  confused 

I have disconnected the instrument cluster and I get the same readings 

Ive started to strip out the wiring harness in the engine bay to the brake module 

to see if the fault is there

there is a main plug in the passenger foot well they all look ok 

[Tdci-Peter]

22 minutes ago, waynes had enough with it said:

the fault is on the ms side

but the abs is on the hs side  confused 

I am suspicious of that diagram. It all a bit pretty & non-technical, such diagrams are very prone to errors. The international OBD standard was primarily aimed at emmissions testing, and that always requires access to the ECU or PCM. And the universal standard pins for this is 6 & 14. The 3 & 11 pins are a Ford specialty, used,as far as I know, always for the MS CAN bus. So all the hard evidence I have seen points to 6 & 14 being the HS CAN, going to the PCM. I can't be 100% sure, Ford do do some very strange things. But many generic scanners do not use 3&11 at all, and simply would not work if 6 & 14 did not go the the PCM.

[unofix]

If I was a betting man (but I'm not) I would bet the problem lies with the BCM connector. Regardless of wether the problem is the HS or MS can, both of them eventually find there way to the BCM.

Since the BCM has a termination resistance of 120 Ohm then if you unplug it and retest the pins 6 & 14 you should see a change. Under normal conditions the resistance of 6 & 14 is as you know 60 Ohms (approx +/- 2ohm) since you have just over double that resistance it is indicating that one of your termination resistors is missing

[waynes had enough with it]

26 minutes ago, unofix said:

If I was a betting man (but I'm not) I would bet the problem lies with the BCM connector. Regardless of wether the problem is the HS or MS can, both of them eventually find there way to the BCM.

Since the BCM has a termination resistance of 120 Ohm then if you unplug it and retest the pins 6 & 14 you should see a change. Under normal conditions the resistance of 6 & 14 is as you know 60 Ohms (approx +/- 2ohm) since you have just over double that resistance it is indicating that one of your termination resistors is missing

That’s what I was thinking maybe the BCM is at fault

ive unplugged and tested terminals 6-14 and nothing open circuit 

ive taken the BCM apart and inside no signs of water ingress 

[waynes had enough with it]

15 minutes ago, waynes had enough with it said:

That’s what I was thinking maybe the BCM is at fault

ive unplugged and tested terminals 6-14 and nothing open circuit 

ive taken the BCM apart and inside no signs of water ingress 

I also have a galaxy can I take the BCM out and try it on the mondeo and just check the resistance only on them pins and see if it’s the same or not or try the mondeo one in the galaxy to see if it’s ok on resistance 

[unofix]

Hi Wayne, can I just confirm that I understand you. When you unpluged the BCM and tested the resistance on the pins 6 & 14 of the OBD2 connector they were "Open Circuit".

If that is the case that they are open circuit  with the BCM unpluged then it is indicating that the fault is at the other end and the BCM is OK.

With the BCM reconnected I assume you will get the 133 ohm resistance back on pins 6 & 14 of OBD2.

Now try unpluging the PCM and I expect you find nothing changes, that is you still have 133 ohm. If this is the case then the fault is on the HS can to the PCM, or the connector of the PCM

[waynes had enough with it]

18 hours ago, unofix said:

Hi Wayne, can I just confirm that I understand you. When you unpluged the BCM and tested the resistance on the pins 6 & 14 of the OBD2 connector they were "Open Circuit".

If that is the case that they are open circuit  with the BCM unpluged then it is indicating that the fault is at the other end and the BCM is OK.

With the BCM reconnected I assume you will get the 133 ohm resistance back on pins 6 & 14 of OBD2.

Now try unpluging the PCM and I expect you find nothing changes, that is you still have 133 ohm. If this is the case then the fault is on the HS can to the PCM, or the connector of the PCM

That’s correct 

the PCM is that the engine ECU I will try and unplug it

maybe a bit awkward to get at as the car is parked on grass

and its inside the passenger wing

i will get to it when I get a chance 

[unofix]

Hi Wayne, yes locate the ECU (silver metal colour on your car I think). Just do a Google search and there will plenty of videos/photos

[waynes had enough with it]

On 4/2/2021 at 1:55 PM, waynes had enough with it said:

That’s what I was thinking maybe the BCM is at fault

ive unplugged and tested terminals 6-14 and nothing open circuit 

ive taken the BCM apart and inside no signs of water ingress 

Does anyone have a diagram on the plugs to the pcm so I can test some electrics 

my plugs are double square on the board