Mk4 Mondeo 2.0 TDCI Limp Mode

[Tdci-Peter]

2 hours ago, Dee_82 said:

If it is right, then we are still getting 60 ohms of resistance between two chassis ground points but only under heavy load

I looks ok to me.

The resistance readings, if from the multimeter while the measured circuit is passing current, are false. They are just a scale factor out from the voltage readings.

16mV across the bodywork when passing 17 amps does not sound unreasonable. Steel is a much poorer conductor than copper, even though there is a lot more of it. That leaves about 75mV over the 6mm^2 cable from the ground point to the 1st splice, SP518. At 17A this would be 4mohm, or about 1.3m of that cable, which sounds possible to me. There would be a little bit of extra resistance at both ends, in the crimps, but 0.004 ohms is a reasonably low value.

The voltage drops between the two splices are negligible.

[Dee_82]

Thats a little disappointing, lol. That being the case I'm back to ABS... Or CAN, or maybe even the CJB.

Or perhaps a signal ground. . Just seems strange there's so many little electrical issues.  That app peddle being one easy to test

 

[Dee_82]

So  I managed to test the CAN network along each of the nodes, SASM, ABS and Yaw. 

They all shows around 60 ish across the wires, so in terms of the physical network, it appears to be fine.

Since the earthing appears normal im going to take another look at the APP

This is clearly a problem and theres only 6 wires that can be doing something wrong, the peddle is fine.   Heres the Wiring diagram for that section.

1. SSAN = ?
2. AS = ?
3. GND via CJB, not directly connected to Ground.
4. GND for Pulse Width Modulation
5. Pulse Width Modulation Signal (?)
6. Spread Spectrum Pulse width Modulation (?)

Im pretty sure ill need a scope to measure whats going on here accurately? I have no idea what pin 1 and 2 are supposed to be though.

As well as looking at this I think I might see if I can get ahold of VCM and try updating some modules. ill need IDS to change the CJB or ABS anyway so its probably a handy think to have about.

 

 

[Tdci-Peter]

7 hours ago, Dee_82 said:

I have no idea what pin 1 and 2 are supposed to be though.

I am quite confused by the drawing, too. The critical part is that there should be two entirely independent senors, and this almost invariably needs 3 wires per independent sensor. Ground, supply and signal. The signal will either be analogue (just a voltage) or digital, either a coded output or a simpler PWM type output. The independence of the sensors is intended to eliminate common cause failures that might cause out of control acceleration.

Using that basis, my best guess for the wiring is the CJB has an analogue signal (AS), an analogue ground (GND_A), an analogue reference voltage (SSAN, or Sensor Supply Analogue?). These three are marked as a twisted triplet.

Then the PCM sensor has a PWM signal (PWMS), a PWM ground (GND_PWM), and a PWM supply (SSPWM or Sensor Supply PWM?). The fact that the supply comes from the CJB does not invalidate the independence as long as there is a separate route back to the battery, and the CJB has several busbars, with different routes to the battery.

This is very similar to the Focus Mk2 system, with 3 wire analogue to the IC, and PWM to the PCM with separate ground and supply. In fact the pin numbers, having just compared them, are identical to the ones on the Mondeo drawing.

With a PWM signal, the actual signal voltage should not be critical, it is only the timing (pulse widths) that matters, so this suits connection to the PCM which is rather remote from, and on a rather different earth reference to, the cabin electronics like CJB & IC. Hence just the one wire actually goes to the PCM.

My model, which may be entirely wrong (!), can be tested partly by measuring voltages, 5v typ for the analogue supply, 12v typ for the PWM supply, and both steady with no ac component. PWM signals will read more or less right on a multimeter (with a scale factor for any reference voltage difference), but will have an ac component that will read as ac voltage on most multimeters, and certainly would be visible on a scope.

[Dee_82]

10 hours ago, Tdci-Peter said:

Then the PCM sensor has a PWM signal (PWMS), a PWM ground (GND_PWM), and a PWM supply (SSPWM or Sensor Supply PWM?). The fact that the supply comes from the CJB doe not invalidate the independence as long as there is a separate route back to the battery, and the CJB has several busbars, with different routes to the battery.

 

That Makes sense, what you cant see in that picture above is that SSPWM does run off to a relay in the power distribution box (R7) and then the battery, it does enter the CJB but not through internal circuitry. 

1. SSAN = Sensor Supply For Analogue N...
2. AS = Analogue Signal
3. GND_A = Ground for AS ( via CJB)
4. GND_PWM =  Ground for Pulse Width Modulation
5. PWMS = Pulse Width Modulation Signal
6. SSPWM = Sensor Supply For Pulse Width Modulation

So one of those two is not playing nice, its labelled as APP-E in the DTCs

===PCM DTC 
Code: P2127 - Throttle/Pedal Position Sensor/Switch E Circuit Low Input

Code: P060D - Internal Control Module Accelerator Pedal Position Performance

In my mind that would narrow down the problem to be on 4, 5 or 6?

Just checking the other diagrams, turns out that R7 actually powers quite a bit, R7is controlled by the CJB...  

• IC
• SASM
• Yaw Sensor
• APP (PCM) Sensor

 

[Dee_82]

okie dokie, So I have IDS up and running, it reports the same problems with the ABS talking to SASM.  In any case pin 6 on the throttle is producing 12.4v, the ground on pin 4 is 0.4 ohms off and 3 ohms with the ignition on engine off.

The only one I didn't check is pin 5 which goes off to the PCM

Now for something a little odd

So whilst I was monitoring the Engine PIDs I started switching on and off various things. 

When I turned the max window clear button on (fires up max blowers, heat, window demist) the variable vane position changed from a reading of around -50v to -65. Thats not much but it is noticeable. I thought it was simple the engine load increasing but it turns out that if I tried max blowers or window demist , headlamps etc it didn't always do it despite the noticeable change in engine noise.

Now for the odd part, then all of a sudden I started getting a metallic engine whining noise, dipping the throttle didn't stop it but a few seconds later it stopped on its own accord, slightly nervous and curious if I could reproduce it by fiddling with the blowers and window heaters, the change in vane position didn't happen at all, nothing at all then changed it unless I dipped the throttle.

Something else thats a little odd is last night I could have sworn the headlamps with dimmer, slightly more orange than normal, by the time I got home it was fine but again, just another weird one. 

My first thoughts was the alternator but its putting out good volts and it can sustain them regardless of the load around the 14.2-14.5 mark.

Something IDS did pick up on again was another DTC. u0100

 

 

 

 

 

[Tdci-Peter]

18 hours ago, Dee_82 said:

My first thoughts was the alternator but its putting out good volts and it can sustain them regardless of the load around the 14.2-14.5 mark.

Alternators can develop some quite odd faults, if it is only 1 phase then then output will only be reduced a little bit, but the amount of ripple that gets into the car's electric supply will increase a lot. Alternators produce a 3 phase alternating output, that is rectified to DC. With all 3 phases, then, a bit like a 6 cylinder engine, at least one phase is near its peak all the time, so the current ripple is minimised. One phase operating below par would increase current ripple a lot. And this ripple can upset electronics, as it produces an ac voltage in the big earth cable from engine to battery as well as in the supply cables.

I assume you have checked the tightness & condition of the major earth and supply cables.

Measuring this ripple with a multi-meter on ac voltage range might be possible, but would only give a rough idea, and results will vary from meter to meter. A current clamp on the earth cable and a scope would give the best results, but is not equipment that is likely to be to hand.

I am not confident this is the problem, alternator faults tend to get worse quite rapidly and then become more obvious. But I have known cases where a dodgy alternator did very strange things to the accelerator pedal and other electronics. But there were other symptoms, like warning lights on, in these cases.

[Dee_82]

2 hours ago, Tdci-Peter said:

Alternators can develop some quite odd faults, if it is only 1 phase then then output will only be reduced a little bit, but the amount of ripple that gets into the car's electric supply will increase a lot. Alternators produce a 3 phase alternating output, that is rectified to DC. With all 3 phases, then, a bit like a 6 cylinder engine, at least one phase is near its peak all the time, so the current ripple is minimised. One phase operating below par would increase current ripple a lot. And this ripple can upset electronics, as it produces an ac voltage in the big earth cable from engine to battery as well as in the supply cables.

I assume you have checked the tightness & condition of the major earth and supply cables.

Measuring this ripple with a multi-meter on ac voltage range might be possible, but would only give a rough idea, and results will vary from meter to meter. A current clamp on the earth cable and a scope would give the best results, but is not equipment that is likely to be to hand.

I am not confident this is the problem, alternator faults tend to get worse quite rapidly and then become more obvious. But I have known cases where a dodgy alternator did very strange things to the accelerator pedal and other electronics. But there were other symptoms, like warning lights on, in these cases.

 

The squeal was certainly a new one on me, its not something ive heard before and ive had alternators drop out and die, of course it might be coincidently and just another thing going wrong. 

The main earth strap was removed and cleaned , I haven't checked the main supply cables from the alternator.  Ill give them a clean and reconnect them up. So if one of the phases on the alternator is going wonky due to a nackard diode or something, it would introduce a AC like wave form? across the battery although ideally across the alternator would be best to test?

what kind of range would you expect to see? mV's I guess?

like yourself im not at all sure this will be the problem since the APP error is with engine off or on.

[Dee_82]

So at idle, its around 0.014v, under light load, its around 0.06v, if I slap everything on it can fluctuate between 0.06 and 0.08. it can sometimes spike to over 0.1v but settles.

DC voltage is 14.7v at idle, it can drop momentarily to 13v when turning things on but settles around 14.4 and 14.7

[Tdci-Peter]

3 hours ago, Dee_82 said:

it would introduce a AC like wave form? across the battery although ideally across the alternator would be best to test?

The trouble is, the battery is very good at smoothing out AC voltages. If you were measuring 60mV to 80mV rms of AC voltage direct across the battery, I would be tempted to say either there is a large AC current, or the battery is a bit old and high impedance. But it is not something I can recall ever trying.

Another problem is that multimeters can't distinguish between voltage steps at a fairly slow rate, and proper AC voltage at decent frequencies like 50 to 500Hz. The spikes you see may be small voltage steps due to some load switching on & off.

I have just been looking at automotive alternators on the net, I have never dismantled one! It is hard to find what the output ac frequency is, it depends on the pulley ratios to get to alternator rpm, and then the number of poles on the rotor.

But as you said, some of the faults you have can happen with the engine off (battery only). Also the ability to deliver full voltage with large load variations at low engine speed is not consistent with a duff alternator. Some voltage steps when the load changes are normal. It does take a little while for any alternator to respond as the rotor current has to change, and it is a large inductor which resists rapid change. So alternator does not stand as suspect no.1 in my ratings!

 

[Dee_82]

Well, im running out of ideas. It bombed in to limp mode again today

I had left the codes on after the last test I ran, changing them from states B8 to 08 which is basically Not Currently a problem.  

• U0100:00-08 - ABS (Lost Coms with ECM/PCM A)
• U0126:00-08 ABS (Lost Coms with SASM)

After the limp mode it added these

• U0401:68-48 - ABS (Invalid data received from ECM/PCM A)
• P2267:73-24 - PCM (Turbocharger A Boost system performance - Actuator stuck closed)
• P2263-P - OBDII (Turbocharger A Boost system performance)

I was able to stick the car in Neutral, turn off the engine, feet off the pedals and leave it for 5 seconds before turning on the engine, re engage the gear and continue as normal. it cleared the malfunction but left the codes above.

This time I left the fan on the lowest speed, I did disengage the AC since it doesn't work shortly before hand but apart from that there was nothing going on, steady 2000RPM, 70MPH, CC was in use but it doesn't seem to matter if I use it or not, there was a noticeable jolt when it dropped in to limp mode.

I have no idea where to go now, it seems quite a few folk have had similar issues but as far as I can tell, not a single person resolved them or they all just fixed it and buggered off from the forum!

[Dee_82]

another bit of info from today.

So we drove about 400 miles today, approx. every hundred miles or so it dropped in to limp mode, I actually tried to reset the codes again on the move and it worked for about 10 min when it bombed out with not only the traction control light illuminated but also the engine fault light. reading the codes showed the turbo actuator as moving from pending which is where it normally was after a limp mode to EML light displayed.

there was also a loud ticking sound coming from the BCM, it sounded like rain drops but was clearly one or more relays tapping away, it would come and go for no apparent reason we could work out. might be entirely unrelated but who knows. just about ready to give up on this unless anyone has any ideas to try?

[Tdci-Peter]

On 11/17/2018 at 11:35 AM, Dee_82 said:

P2267:73-24 - PCM (Turbocharger A Boost system performance - Actuator stuck closed)

P2267 seems to be a new code that you have not reported before. And it is quite a positive one. The Turbo actuator is directly connected to the PCM, and the code was, I assume, in the PCM. So no comms related problems. The PCM gets a direct reading of Actuator position, so to report this code then it would seem either the actuator was stuck closed, or there is a fault in the actuator sensor, or there is a fault in the signal or Vref wires between PCM & actuator,

P2263 is a bit vague, MAP, or some other sensor in the system could make the PCM think there is a general turbo problem, but a direct report of stuck closed (P2267) is more likely to be genuine.

Before getting carried away and replacing the turbo or its actuator based on this, I would try to replicate the code.

It could be the ABS related errors are a separate problem to the turbo, and you are not getting limp mode as such, but if the turbo vanes did stick closed you would get reduced power from the engine without any deliberate safety related action (limp mode) from the PCM. In that case the EML is not so directly related to the reduced power, the direct relation would be turbo actuator to power, with the EML coming on for reasons either of comms errors between ABS & PCM, or turbo failure.

[Dee_82]

When the car goes in to limp mode the turbo seems to freeze its vane position where it was which allows the car to operate albeit with significantly less power.  Is that normal behaviour with limp mode?

also curious to know if anyone has had their BCM make it sound like its raining, its a rapid and possibly multiple clicking sound that only appears at speed and not reproducible, its entirely random. No outward signs of problems on the dash but is usually before or after a limp mode activation.

 

As far as I can tell the problems seem to be one of two groups.

Group one - persistent and repeatable

• Accelerator pedal reported low input voltage on APP E (which appears to be directly fed from the R7 relay in the engine bay, through the BCM to the pedal then directly to the PCM
• ABS losses coms with SASM, reported in tests on demand, also reported when car goes in to limp mode. Connection to CAN Good, SASM replaced. Traction control light illuminated when test carried out.
• BCM making all sorts of funky noises at random, suspected Relay(s) no DTCS (possibly CAN interference?)

 

Group Two - Result after Limp mode activation

• Turbo actuator reported as being stuck closed (default position when no vacuum applied to actuator) actuator position sensor fed directly from R2 relay in engine bay connecting directly to the PCM. Initial limp mode shows DTC as pending. Restarting car on the move turns on EML and confirms error. MAP replaced.
• PCM loses coms with ABS (not repeatable on demand) ABS connection to CAN good. 
• ABS losses coms with SASM, also reported in tests on demand. SASM Connection to CAN Good, SASM replaced. activates the traction control light
• ABS received invalid data from PCM

 

 

[Tdci-Peter]

On 11/21/2018 at 9:35 AM, Dee_82 said:

• Accelerator pedal reported low input voltage on APP E (which appears to be directly fed from the R7 relay in the engine bay, through the BCM to the pedal then directly to the PCM
• ABS losses coms with SASM, reported in tests on demand, also reported when car goes in to limp mode. Connection to CAN Good, SASM replaced. Traction control light illuminated when test carried out.
• BCM making all sorts of funky noises at random, suspected Relay(s) no DTCS (possibly CAN interference?)

Also the Turbo position reads low, sometimes.

It would be crazy for the PCM to intentionally shut down the turbo to initiate a reduced power mode (limp home mode), and then to flag up a DTC complaining that the Turbo position reads low simply because it has shut it down. No programmer in his or her right mind would allow that. ..... But programmers and "right mind" don't usually go together, so maybe. With all this over clever software anything is possible, however it is still unlikely.

Intermittent loss of one of the 12v battery supplies could cause all that, but I suspect finding a common supply point for SASM, APP and Turbo position would be also unlikely.

BTW, where is the wiring info from, if that is an answerable question. It is very hard to locate any wiring info unless you have full access to Etis, which comes with a hefty price tag.

If CAN interference was making the BCM turn a relay on & off rapidly, I would expect to see U type DTCs in the BCM. It is hard for CAN messages to be mis-read without detecting that the message was corrupt. It is not an ABS/ESP related noise is it? I get a sort of hissy clicking that sounds like it is coming from the passenger footwell (where my BCM / fusebox is), but only on bumpy bends. It stops when the ESP is turned off, so I am sure it is the ESP being over-sensitive, and the noise is probably the ABS itself, just the other side of the bulkhead.

If the relay clicking is not related to some function, then the intermittent power loss suggested above could be the cause.

I think I would try to hook in a voltage monitor of some sort to one of the suspect supplies, like the APP, probably using scotchbloks or something. Bit yuk, I know, but desperate times ...  Unexpected dips in the voltage would show a wiring fault, that could probably be bridged with another wire if it can be roughly located.

 

[krisjones]

did you ever find the problem with yours. mines going into limp mode within a street distance in the morning. but pulls like a train. ii had it put on a diagnostic, codes came up p1632 p2263 p003a. mechanic suggested my actuator is sticking. but it only happens when driving sedatly. if i boot it it flies? 

[Dee_82]

Na, not a scooby. 

Ive pretty much given up, the only things ive not really changed are the PCM and the brake control module, one costs quite a bit and the other is a complete PITA. im not prepared to spend big money repairing this so ill just need to live with it and hope I can get shot of it, besides that im having trouble starting in the morning, starter is struggling to turn it over, which is another sign of immanent doom as the clutch falls to bits and im getting some awful knocking on the NS shock. Im going to take some degreaser to the strut and see if they notice at the MOT next month 😄

Two of your codes suggest that the garage is correct, its a boost problem which might be the solenoid, the actuator sensor or the actuator itself either because its nackard or because the turbo vanes are gummed up.  

A sticking actuator might be any one of the above problems or some weird electrical gremlin, Ive tried driving erratically over 400 miles and it still happened.  You have two choices, take a look for yourself, make sure the solenoid is working, maybe swap it with the one for the anti shudder valve (As you look at the right side of the engine, there are two red/purple coloured solenoids attached to the engine itself, the one closed to the front is the anti shudder valve, the one to the back is the boost solenoid, they are both the same. check the hoses, if possible check if your losing pressure on the lines. Maybe get a ELM 327 device and forscan, monitor the vane position sensor and see if it does anything wonky. look back at the posts on this thread for some idea of what your looking at. beyond that, anything you can do will be based on your time, ability  and how big your wallet is

 

[krisjones]

im getting trouble with the starting as well. brand new battery less than 2 months ago and its struggling after short journeys. i think im gonna cross my fingers and part ex it and hope it doesnt go in to limp mode when its tested to be part exed. the other odd thing is it always goes in to limp at the same time in the morning. about 3 mins into journey. but doesnt do it when im driving home in the afternoon. the boost on the turbo is phenomenal. i can put my foot down and not have an issue. but that sedate drive for the first few minutes early morning and bang limp mode. 

[Tdci-Peter]

1 hour ago, krisjones said:

im getting trouble with the starting as well. brand new battery less than 2 months ago and its struggling after short journeys.

DTC P1632 is linked to an alternator fault. If the battery is failing after 2 months there are two likely possibilities:

1) Wrong type of battery. Ford insist on a silver calcium type for most of their more recent cars, or EFB type if you have stop-start. Some older style batteries can not cope with the Ford charging system.

2) A fault in the alternator or its wiring. This fault has been linked to the wrong type of replacement alternator being fitted. But broken wires, bad connections or internal faults in the alternator could be the problem.

Alternator faults can also cause a range of other odd symptoms, as they put voltage ripple onto the main supply. The way the light comes on after starting, when the charging system is being stressed the most, also puts the alternator near the top of the suspect list. It is re-charging the battery after starting as well as a higher than usual driving load.

 

[krisjones]

i have the standard key version, no stop start. could be a failing alternator. its on its original. to be honest i am done with it. iv already spent over a grand on it in the last two years. its a fantastic car when its working properly. so comfy and fast but i think its at that age where it needs to go. will pop for a grand on part ex and hope it holds together lol

[FatHead1979]

11 hours ago, krisjones said:

i have the standard key version, no stop start. could be a failing alternator. its on its original. to be honest i am done with it. iv already spent over a grand on it in the last two years. its a fantastic car when its working properly. so comfy and fast but i think its at that age where it needs to go. will pop for a grand on part ex and hope it holds together lol

Specfically, what battery is fitted to the car?  If it's a regular lead/acid type, especially if it's not of the correct capacity, the Smartcharge system will barbeque the battery in no time at all.

[Dee_82]

Good luck getting a grand for a 08 Diesel! I tried we by any car who initially stated about a grand who promptly reduced the value to about 400 quid after their "Detailed Inspection" which is to say a complete understatement, it might as well have been judged for some Classic car competition, unless its in perfect nick, which a 2008 car is unlikely to be they will just keep turning those screws. Private sale would yield more but I cant look someone in the eye and sell them a dud

Anyhow, my final update on the Mondeo saga, ive given up entirely, my partner even pointed out that ive started parking it out of sight. the Front left strut sounds like its about to fall off, it struggles to start which is  sure sign the clutch is on its way out, the other day it just randomly turned off mid drive, no warnings, no DTCS.  Somehow it managed to pass its MOT with flying colours but now its time to say goodbye. so part ex it is 😞 

As long as I can get it started and drive 25 miles down the road, we are off to exchange it in for a Focus.