C5 2.0 Hdi Limp mode when warm

[Johnd993]

My 2015 C5 2.0 diesel is ok in morning. Drives fine no warning lights. After driving around 15 miles and parking - I return to find car starts but reving at 2000 revs constant with throttle unresponsive (limp mode). Engine management light on - ‘Service’ light on - ‘Asr/Esp fault’ on dash. I can drive with no throttle to get home. Next morning - all fine again till driven 10-15 miles when above repeats. Code P11B4 comes up on OBD. (Snapon) Will not reset when warning lights on. Will reset next morning.
P11B4 is fault in throttle but think this is the limp mode signal disabling throttle. Anyone got any ideas? Problem started few days ago. Had new cambelt and clutch a month ago. Weird that it is ok when cold in morning. Would Lexia diagnostics drill deeper into fault codes?

[GiveMeABreak]

P11B4: Is an accelerator pedal sensor fault - Engine reconfiguration activated following an electrical fault.

Basically, the accelerator pedal has a 2 track potentiometer. If it detects a fault on Track 1 it uses Track 2, it the fault is on Track 2 it uses Track 1, but if there is a fault in the coherence between the signals of the 2 tracks then the engine management ECU puts the engine into down grade mode.

So the likely problem is the Accelerator pedal sensor or the electrical harness.

Resetting it won't fix the problem. If it is intermittent, it will reappear again, once the signals from the tracks are out of kilter again.

Pop up your VIN if you want the part number.

[Johnd993]

Thanks Marc. Brill. Vin is VF7**************[VIN obfuscated, can be read by forum staff]

[GiveMeABreak]

Ok, so you have the 2.0 DW10FD 150 Engine.

The Accelerator Pedal (throttle position sensor) is part number 1601EH and is £260.78 inc. VAT from Citroen brand new.

Part number 1601EH is the one fitted to your model from new, but some earlier models of the X7 had this fitted as a superseded replacement part - so although the one on the bay would of been an earlier one - it is compatible because they were replaced with your part number a few years later.

This is a used one on the bay here:

https://www.ebay.co.uk/itm/Citroen-C5-P ... 2236415724

This one is £75 plus £8 postage.

Before replacing, make sure you don't have any other fault codes and double check the connector on the accelerator - make sure the contacts are clean and making good contact.

[Johnd993]

Thanks Marc. This is beyond my expectation of the help you are giving! I have taken the following numbers off the pedal box... RB 0 280 755 173
PSA 96 720 912 80 AO0866-D02.
The first of these RB 0 280 755 173 differs from the one you suggested on ebay as that ends 127 instead of 173. Do you think it matters?

[Johnd993]

I have seen another on ebay with the exact numbers. Contacting him now.

[GiveMeABreak]

Each part number is unique John, so will naturally differ, as they are coded internally by the manufacturer plus have a European identifier.

As the seller already listed the VIN form the donor vehicle, I have already checked it out and confirmed that your accelerator part number was a replacement, as you can see from the donor car parts below:

the RP is 'Replacement Part' and that corresponds with your original part number (1601EH) that was fitted to the model in later years. So yes is fine.

[Johnd993]

Perfect. I just hope thats the issue. I’m on it now so update in a few days. Really appreciate your time. Top bloke!.

[Johnd993]

Hello again. Update.... Not great news. New accelerator pedal (throttle poistion sensor) fitted. Has not fixed problem. P2138 and P11B4 codes.
I did start and drive it before ‘calibrating’ it (3 slow press down & up) but have done that since - no difference. It drives perfectly with no dash lights for a long while but when stopped and locked and return 20-40 mins later its in limp mode with ‘service’ ‘asr/egr’ etc on. After driving a while and switching off it sometimes sorts itself out and drives normally again. All wiring and connections examined and wriggled - nothing seems untowards. Whats my next step?.

[GiveMeABreak]

John, sorry to hear that has not resolved the issue - as so often it can be a combination of factors that are at play. At least you can sell it back on as a used part.

I've no specific details on this particular engine as it is a late 2015 DW10FD engine, that uses a Delphi 6.2 Engine Management ECU. The fault codes can vary between engine types slightly and have different values for when the code is triggered - and again for the cancelling of the fault.

So I'm reluctant to put up the fault code descriptors for a different Delphi system as I guarantee they will be different in some way.

Diagbox would provide some further info and check for some codes that a generic scanner won't find as well as getting you some live data. However at this point and with the possibility of other related codes it may be a trip to get it thoroughly diagnosed with the dealer given that this is one of the newer incarnations of engine. I don't have an electrical diagram of this engine either I'm afraid.

[Nemo26]

You should look at wiring diagram. Check voltage, ground, and signal. Ideal is osciloscope for signal. You have wiring issue, or ecu fault.

[Johnd993]

Hi guys,
My wiring all seems good so think best option now is to replace ECU. I can find one on ebay and attach pictures - the first is my ecu - the second is the one for sale. The primary numbers match (Delphi DCM6.2A 9804828580). But other numbers vary. Can you tell me if compatible?
Also my local ecu re-programmers havent got the software for this later version. Know if any others? Dont mind travelling or sending.
Thankyou.

[Johnd993]

Sorry - the second one is my ecu.

[Johnd993]

You have all gone quiet but anyway thought worth posting update / conclusion.
It was the throttle position sensor on the intake. The whole unit with the butterfly valve inside was required. Found one for £30 (bazzaarly from Ford Focus). Problem solved.

[GiveMeABreak]

Hi John, yes sorry, it has been quite busy here lately, but I'm glad you have found the culprit, and thanks for posting your update. This will surely help others with a similar issue in future.