C5 Mk2 2.0 HDi has a nervous breakdown on the M4

[masood_ilyas]

This refers to a C5 Mk2 Hdi Automatic year 2006 with 80500 on the clock and looked after reasonably well.
The Auto gearbox oil was changed at 65000 mile and the engine oil at 80200 as part of its recent turbo repair and DPF Depollution related issues sorted so it was a pleasant experience to drive it on the M4 last weekend heading towards Wales, but then just outside Reading out of the blue doing 70 the C5 decided to have a breakdown! All of a sudden it went into “PC Crash mode” the speedo console lit up like a xmas tree and the messages flashed on the multiscreen saying Faulty gearbox, faulty stability system, depollution fault all the light on the speedo console lit up showing gearbox was selected in P,R,N,D and also the manual gears selected were 1,2,3,4,5,6. The engine management fault light was ON including the Snow flake and the Sports mode all of these simultaneously!. The car slowed down from 70 mph to 25 and went into a sort of limp mode.
I could drive it in that mode to the Chievely service station 3mile further away but thinking if the bands and clutches have gone it was best to park it on the hard shoulder. Switching the engine off and restarting made no difference it still flashed faulty gearbox and depollution fault amongst others.
The AA recovery chap came and transported the family and the car back to London.
Next morning after a cooling down period the car started as normal with no fault messages even the engine management light went out as normal after starting and I was able to drive for a few hundred yards in its lower gears but did not risk any higher speed.
I then hooked up the Lexia and found various faults listed but the main theme was the Engine management system communication giving wrong or no data to the other sub system, interesting one was “Too many faults happening together can not log them so they will be ignored.”

Some of the error code were:
Fault D208 No communication with engine ECU Data invalid (Family ABS * )



Fault 1165 Fuel Pressure Signal Pressure too Low
Fault 9522 Saturation of the log of faults BSI ECU (Too many fault events recorded at the same time: these events temporarily ignored)



Fault U1208 Remote fault, permanent fault, information sent by engine ECU incorrect value received
Fault 1605 Torque requested by driver information transmitted by engine ECU incorrect value received.
Fault P1727 Engine torque information received by CAN incorrect value received.
Fault 1830 Gearbox issue, Front wheel speed information transmitted by ECU (ESP ) incorrect



Fault 5390 Engine torque regulation
Fault P05D2 Remote fault, Temporary fault, Data invalid engine ECU incorrect value received
Fault F406 Engine oil pressure sensor











So my question is, was it the BSI box having a melt down due to some sort of dry joint on its PCB or other component unreliability because until then the car was fine with plenty of power. More important what next Change all the ECU, how does one go about resolving this, skip would be one of the suggestion but surely not!


Thank you for reading all this, any suggestion will be appreciated

Masood

[RichardW]

You can't make any sense of that.... clear all the faults and see if any come back as permanent. Then take it for a drive to see what happens!

[EDC5]

It sounds like a major comms issue between various ECU's to me.

Could this be something like a short circuiting of the Engine CAN bus that links the Engine ECU, Gearbox ECU and ABS to the BSI?

[Michel]

Clear all of those faults.

Take it for a drive.

Read faults again, post the results.

[C5 and P2 2-8-2 fan]

I think I would be inclined to do a battery disconnect and a proper BSI reset, certainly wouldn't do any harm, the procedure is detailed in a thread on here somewhere I believe, hope this helps.

[masood_ilyas]

Thank you all.
Yes it makes sense to clear all faults followed by a BSI reset and a recheck of errors.
I will update this post when I have done it. Thanks

I miss my old 1958 Ford Prefect ,
its ECU/BSI consisted only of an ignition coil, sparks plug and a distributor.
Oh happy days of youth.

Masood

[GiveMeABreak]

There is likely to be more to it than a BSI reset - to have such a communication failure of so many components at once. Although one fault can cause a cascade of other errors, so I would also check on recent work done - you say you had the turbo replaced - I would check the Turbo Position Copy Sensor and any and all electrical and sensor connections in that area for a start. Check your alternator is charging, the battery condition, electrical connections first. The check all recent work and trace your steps back and double check everything.

[Gibbo2286]

I seem to recall reading somewhere that there was a known fault on some C5s where a cable near the BSI was chafing on a bracket and causing insulation to break down, I'll try and look it up.

Found it but it wasn't the BSI it was the DPF temperature sensor wiring "Code P1421 MIL illuminated replace sensor and re-route cable as necessary." Applies to all 2004-2008 models with DPF.