Czech C5 depollution system faulty qwhen going full out

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mcduff
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Joined: 06 May 2019, 17:10

Czech C5 depollution system faulty qwhen going full out

Post by mcduff »

I have an October 2008 C5 Tourer Exclusive, automatic 6-speed gear, new type, 100 kW 2 l. HDiF engine
VIN VF7**************[VIN obfuscated, can be read by forum staff]

First owners put on 145 000 km in 9 years, since October 2017 I have put another 47 000 km on top. When buying the C5, my local garage gave it a complete overhaul with new filters, belts, the works. Nothing done on the environmental exhaust system or its additive.

After several months, the Engine management light came on, with the display error "depollution system faulty". It went away after a few days, came back weeks later, went away, etc etc. The garage diagnosed it, tightened and cleaned some things, and almost a year no problems.

Then it came back some months ago. I went to the garage each time, they reset it, all OK. Two weeks ago, the car went in for a service job, including all filters, brakes, etc etc, in preparation of a long trip to Slovenia (from the Czech Republic, my home base).

When driving through winding roads going uphill, I accelerated going uphill at 70 km/hr and the light went on. At that time, the "additive too low" remark came up as well. Reset in a local garage 30 km further: pressure too high. Continued driving, 1700 km, no problems. Just before coming back, again light came on after acceleration. Reset with checking fault codes. Then I tried to redo the circumstances. Going 110 km in 6th gear, slowing down before corner to 85 km/h, then going into the right-hand corner full gas, car downshifted and accelerated. While finishing the corner, the depollution faulty light came back on and the power fell away.

Every time the error came up, I immediately lost power, and and also the cruise control stopped working. After a few contact on-off, the cruise control and power came back, but the light stayed on longer.

My garage uses the Hella Gutmannn Mega Macs PC diagnostic system.
The last time, the following fault codes came up:

Error code P0088
Pressure fuel system
> too high pressure

Error code P1671
regulation speed
> error function

Error code P1166
Pressure difference pressure sensor
> error signal

Especially with the last error code, the translation might not be completely accurate, please follow the number, not my translation. The error code P0088 is new, did not appear earlier.

My garage is not sure what the problem is, and just repairing everything would be very expensive. In addition, the pressure sensor they saw on the spare parts catalogue for this engine is not the same as what I seem to have on the engine.

Any idea- remarks reading this?
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GiveMeABreak
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Re: Czech C5 depollution system faulty qwhen going full out

Post by GiveMeABreak »

I've answered your Additive query in your other post.

The above will happen as a result of the engine ECU going into a backup mode at some point. This will limit power to reduce engine damage and pollution levels until you get the issue resolved.

P0088: High pressure fuel regulation: The measured rail pressure is too high in relation to the set point

Cause: The ECU detects a difference of 180 bars to 250 bars for 3 to 6 seconds between the rail pressure set point and the measured rail pressure

Down Grade Modes:
  • Deactivation of processing of the accelerometry
  • Deactivation of the accelerometry strategies
  • Deactivation of the detection of loop difference on the fuel flow rate regulator
  • Deactivation of the injector flow rate correction strategy
Symptoms Likely:
  • Jerking/stalling
  • Unwanted acceleration
  • Noise
  • Smoke from the exhaust
  • Lack of power
  • Starting problem
Suspect Areas:
  • Engine ECU (Software not up to date)
  • Poor fuel or polluted fuel (petrol, deposit, etc.)
  • Problem on the fuel low or high-speed circuit (hose, tank, diesel fuel filter, etc.)
  • Fuel injectors
  • Engine fuse box
  • Electrical harness
  • Connectors
  • High pressure fuel pump
  • Fuel high pressure sensor
P1166: High pressure fuel regulation: Measured rail pressure higher than the maximum pressure. This will be caused because the pressure of the fuel high pressure common injection rail measured is higher than the maximum pressure of 1800 bars for 6 seconds.

Down Grade Modes:
  • Deactivation of the speed limiter
  • Deactivation speed limiter until the next time the ignition is switched on
  • Deactivation of the cruise control
  • Deactivation cruise control until the next time the ignition is switched on
  • Request for Delayed Engine Stop
  • The ECU limits the fuel flow
This will result in a lack of power, hesitation and cutting out.

Possible Causes:
  • Electrical harness
  • Connectors
  • High pressure fuel pump
  • Engine ECU
  • High pressure fuel sensor
P1671 will be simply be because the cruise has been disengaged as a result of the main fault as a safety measure whilst the other fault exists.
mcduff
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Joined: 06 May 2019, 17:10

Re: Czech C5 depollution system faulty qwhen going full out

Post by mcduff »

:cry: 8-[

So it seems my garage was not so far off as to say that it could be several things and not that easy to diagnose. Is there any way to cut down on the possibilities for what is wrong apart off repairing everything? As long as the error stays away, the engine seems to run smoothly and without problems, starting also. Does the moment of the problem occurring, and the way how it disappears itself is any indication?

I just had a 800 GBP full service and brake repair action behind me, have to do the additive filling as well this week, so $$ is a bit tight at the moment, but I also do not want to wreck my car. To put things in perspective, a gross minimum wage here is around 450 GBP, and both privately and for our small non-profit, this is hurting.

From the VIN, can you see what sensor this car should have? They looked it up, but saw something completely different in the catalogue from what I have in reality. That non-fitting sensor costs about 300 GBP, without any guarantee that this is the problem and all would be ok after replacing it.

Before I forget, please imaging several thumbs-up similys here; the reaction speed and info from this forum is sterling work!
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EDC5
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Re: Czech C5 depollution system faulty qwhen going full out

Post by EDC5 »

Could the DPF be nearing the end of its useful life and be somewhat blocked leading to high exhaust backpressure?
I also get the code about the fuel pressure P1166 but it comes and goes after a restart. I’d be more concerned about the pressure differential from the exhaust sensor.
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Paul-R
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Re: Czech C5 depollution system faulty qwhen going full out

Post by Paul-R »

190Km? Yes, the DPF could be getting blocked with residue that can't be burned off. It may need replacing or, if you're reasonably lucky, it may be possible to backflush it.

You really need to get the back pressure across the DPF read to be sure.
mcduff
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Re: Czech C5 depollution system faulty qwhen going full out

Post by mcduff »

I go to get my EOLYS 176 topped up as soon as I receive it, will aks them to check it as well. THanks
mcduff
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Joined: 06 May 2019, 17:10

Re: Czech C5 depollution system faulty qwhen going full out

Post by mcduff »

Update 2 December 2019.

Topped up the EOLYS 176. Once after that, the light went on, then over 8 00 km nothing, now it starts to come back. Checking some older read-outs, I also found the the error P11AA, with the free translated comment "pressure distribution line pressure sensor".

Interesting point: light came up a few days ago. Once or twice restart no effect, light kept burning. The same day went to get fuel, opened the tank cover, filled her up completely and closed. When switching on the contact, the light was off. Coincidence or relevant information?

I always use Shelll V-Power diesel, so probably bad fuel is not a factor. Any new ideas?
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GiveMeABreak
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Re: Czech C5 depollution system faulty qwhen going full out

Post by GiveMeABreak »

Hi again :)

Ok, so PA11 is the Turbocharger pressure regulation solenoid valve control: Incoherence between the command and the measured turbocharging pressure. Incoherence between the position of the turbocharger solenoid valve and the measured turbocharging pressure for 3 seconds with the engine running, the airflow must be below 40 kg/h compared with the theoretical flow for 3 seconds.

So this will throw the engine management light on. The suspect areas are:
  • Turbocharging pressure sensor
  • Turbocharger position copy sensor
  • Vacuum problem
  • Variable geometry of the turbocharger jammed in the "maximum turbocharging" position
  • Turbocharger: Damaged
  • Turbocharging pressure sensor
I would first check the easiest things like the turbo regulation solenoid. If this is playing up then it will play havoc and the engine management system will go into backup mode:
  • Deactivation of the coherence faults of the flowmeter
  • The ECU stops the regulation of the EGR valve
  • The engine ECU limits the fuel flow
  • Deactivation of the speed limiter
  • Deactivation speed limiter until the next time the ignition is switched on
  • Deactivation of the cruise control
  • Deactivation cruise control until the next time the ignition is switched on
  • The activation of the regeneration of the particle emission filter
  • The ECU stops the regulation of the turbocharger : Change to piloted mode
Have a look here:
https://www.frenchcarforum.co.uk/forum/ ... 08#p627908