C5 X7 Tourer ESP/ABS warnings

[Cynthia13]

We've read a great deal about ESP/ABS warnings reference our 2013 C5 X7 1.6 Hdi115 manual Tourer but are somewhat stumped.
ESP/ABS warning comes up but keeps going on and off on a journey, sometimes doesn't show at all, or jumps on for a few seconds only. Naturally, when the warning comes on any speed related items stop working ...such as Speedo, satnav, gear change up indicator etc. Also engine management light on.
2 diagnostics have failed to find specific issue but mention "CAN communication" and absence of communication.
Codes shown are P1445, U1113, U0121, P0571, U1118, P0500, P1536 under engine management.
001C under BSI and various other systems (e.g. wipers, battery charge)
U1113 under electric power steering
U0121 under OBDII codes ($03).

Battery charge is fine.
Both garages said it would be a nightmare bit by bit process, local Citroen main dealer said the car is too old for their diagnostic system (2013???!!!!).

Any suggestions most welcome.
Many thanks in anticipation
Peter and Carole

[RichardW]

Welcome!

It will likely be one of the P codes from the engine interrupting the signal to the ABS ECU.

Looking these up generically we have:
P-1445 - Additive in DPF too high
P0571 - Cruise control / brake switch malfunction
P0500 - Speed sensor fault
P1536 - Brake pedal switch lack of coherence

I would go after the brake pedal switch first. The speed sensor fault may be pinging up because the switch is faulty. The P-1445 means the DPF is 'end of life' - but usually as long as the pressure is OK and the regens not too frequent you can just tell it that the DPF has been replaced and it will go away happy.

[GiveMeABreak]

Regarding being told the car is too old, that's baloney! Are you sure this is a franchised Citroen dealer? I'd be reporting them if they said that to me as they can't just say that, it's total rubbish. I'm sure Citroen UK wouldn't be too happy if you told them, and could threaten their franchise!

They should be using official diagnostics software and if so they are more than capable of dealing with a 2013 X7!

If you want the full descriptions of the fault codes, please provide your VIN. Please post your VIN in full without spaces - it will be automatically masked from public view after submitting your post & will only be visible to staff.

[Cynthia13]

Hi and very many thanks for your response.
VIN is VF7**************[VIN obfuscated, can be read by forum staff]
Engine JBEU3033785

Reference the "DPF will go away happy"...how do we achieve that. Note C5 is on 134k miles, has covered 41k miles since January 2022.

Reference the main dealer issue, we did indeed telephone a franchised Citroen dealer where I asked the question "do you have the diagnostic equipment for this car" as two non-franchised local garages were rather woolly, one using Auto diagnostics. I was promised a call back....which came from an individual who recommended an auto-electrician locally, and who stated that the main dealer would not have the diagnostic for our car ..too old. We don't think that this was a dealer employee. Hmmmm!

The auto-electrician place said that they could only deal with whatever it is if the fault was actually showing at the time (?the memory) but it was most likely a dirty abs sensor or broken wire. We're not convinced!!

[GiveMeABreak]

No, all BS. You'd not get that from an authorised Citroen dealership - probably from a trainee who hasn't got a clue and shouldn't be authorised to give technical advice!

As for the faults, see below, but as Richard already suggested, I'd start with the easiest and most common - replacement of the brake switch.

The other issue regarding the DPF - that just means that the engine ECU records the amount of Eolys additive that has been injected into the fuel tank. This additive contains Cerine, a compound that reduces the exhaust gas temperature required for the particulate matter to burn off in the filter. The cerine compound itself can't be burned off, so remains int he particle filter walls. It is this, along with other deposits and ash that also can't be burned off, which ultimately lead to the blocking of the filter, which then requires a deep clean or replacement.

This is an estimation by the engine ECU, and the filter may go on working for some time after the warning, but can only be reset with a professional level diagnostic tool, by telling it that a new DPF has been installed. Not really recommended as when it does start to fail (if not already) it will be because the differential pressure sensors are detecting the blockage.

When this happens, it will be because it is literally clocked and can't regenerate any more and you won't have the time to wait before getting the filter removed and cleaned / replaced.

Fault Code:	P0571
Description of Fault:	Intersystems CAN: Lack of coherence of the brake pedal position sent by the BSI. Description of the diagnostics: "main brake pedal switch out of service" information received by the engine management ECU on the CAN.
Conditions for Fault to clear:	Driving for 5 minutes
Downgrade Modes whilst Fault is active:	Reversible deactivation of the vehicle cruise control
Symptoms:	No effects immediately perceptible to the customer No automatic stopping of the internal combustion engine (If the vehicle has the Stop and Start system)
Suspect Areas:	Brake pedal switch Electrical harnesses Connectors

Fault Code:	P0500
Description of Fault:	Intersystems CAN: Speed information incorrect or absent. Description of the diagnostics: Information not received or received invalid by the engine management ECU on the CAN.
Conditions for Fault to clear:	Driving for 5 minutes
Downgrade Modes whilst Fault is active:	Irreversible deactivation of the vehicle speed curbing function Irreversible deactivation of the vehicle speed limiter Irreversible deactivation of the vehicle cruise control Sending of the information "torque uncertain" on the CAN network Switching on of the warning lamp and/or warning message: Warning lamp MIL
Symptoms:	Jerking/stalling Lack of power
Suspect Areas:	Engine ECU Intersystem CAN network

Fault Code:	P1536
Description of Fault:	Measurement of the brake pedal position: Lack of coherence between the two brake sensors detected on deceleration. Description of the diagnostics: Lack of coherence between the main brake and the secondary brake during sharp deceleration for 500 ms.
Conditions for Fault to clear:	Driving for 5 minutes with numerous braking actions
Downgrade Modes whilst Fault is active:	Irreversible deactivation of the vehicle cruise control
Symptoms:	No effects immediately perceptible to the customer Absence of automatic stopping of the internal combustion engine (Vehicle equipped with "stop and start")
Suspect Areas:	Brake pedal switch Fuse Connectors Electrical harnesses

[Cynthia13]

Thankyou both, Richard & Marc, that's extremely helpful and far more so than our dealer experience which we have dismissed as BS. Something very not right there.

On the PEF issue, would a Terraclean be best plan, or might it be better to go for the brake light switch first then consider Terraclean afterwards?

On a journey today we went 20 miles with no issues/warnings then along came EDP/ABS and engine management. Rapidly became EPS off and engine management light, then nothing again.

We're located Mid-Wales, near Landlord (40 miles west of Shrewsbury).......any recommendations for a sensible and trustworthy garage?!
Incidentally, what's involved in changing brake light switch

Excellent forum, cheers
Peter and Carole

[GiveMeABreak]

Hi both, these are at least 3 separate issues. For now, I suggest you focus on the brake switch, as at least 2 of those faults relate directly to that.

You can deal with the DPF cleaning later, but will just have to put up with the nag warning for a while. The P0500 is a third issue, but can be a faulty engine speed sensor. If the engine speed data being sent to the engine ECU is suspect, it will affect how the engine runs and can lead to jerking or power issues.

So not guaranteed, but I would suggest Brake switch, engine speed sensor first and see if that clears those faults. One word of advice relating to sensors, don't buy cheap sensors - they're not worth it and can often be dead on arrival. Try and get a branded one if you can.

[Cynthia13]

Once again, excellent response and a good guide to our next step, far more positive than the two local garages not to mention the franchised main dealer.
We never use aftermarket/spurious stuff.....we have a Jaguar XJS as a classic and only once went for aftermarket.....our Jaguar specialist refused to fit them ...enough said!
Incidentally, predictive text put us as residing near Landlord.....that should read Llanidloes!
We'll post again when we have a result but grateful in the meantime
Peter and Carole

[Hell Razor5543]

There have been Forum members who have managed to clean the DPF themselves, by (IIRC) removing it carefully (the filter is ceramic, and so has to be treated with care), had oven cleaner left in it for a while to soak, and then water run through it (and NOT via a pressure washer or similar) until it runs clean. Then, once it has been refitted, the car is told it has been replaced.

However, please check on the Forum for more information. I would not want to cause you any avoidable problems.

[Cynthia13]

Further to the ESP/ABS warning issue.....replaced brake light switch but to no avail. Next will be engine speed sensor but meanwhile.......thought to carry out BSI reset and whilst battery disconnected (helpful BSI reset post noted) check and clean etc ABS module connector block..... it's visible just under main fuse box but how does the connecting plug fit......is it simple pull extract/push insert or are there fittings which I haven't seen yet? Only taken a cursory look so far.