C5 X7 THP -11 Running rich? Codes P2279 & P0134. Suspension and Engine Cooling fan

[Sami_R]

Hi all,

I'm new member here. Just bought my first Citroen. There is couple of issues with the car that I was were of when I bought the car, but bought it anyway "as is".
One issue is with the cooling fan. It is running all the time. When I start the engine it will start running immediately at full speed and keep running some time after engine is stopped.
Where should I start? Is there maybe some sensor problem or...? In cluster water temperature is acting as it should and there is liquid in expansion tank. It is wrong colour though (green). It should be orange I guess?

[GiveMeABreak]

The first thing to do is get it on 'Diagbox' and run a full diagnostic. Then pop any fault codes up here along with 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). That's the only sensible way to progress as the electric fan can come on for many reasons, so may not necessarily be the engine fan control unit.

[Sami_R]

I have scanned the car with generic OBD scanner. No fault codes, but it will show only engine codes.
Try to find more capable scanner.

[GiveMeABreak]

Yes a generic scanner won't be any good as they generally cannot read the constructor codes only basic OBD II codes.

It needs a professional level diagnostic tool, but ideally Diagbox as that is what Citroen use.

[Sami_R]

Hi, the car is starting to really act weird now. Suspension is not working (low rider now) and there is suspension error message in dash. Also check engine light. Maybe need to change this topic name also.
I have now scanned the car with Delphi OBD scanner. Car vin is by the way VF7**************[VIN obfuscated, can be read by forum staff].
That was not nice when I realized how many codes there was. Feel like hitting the jackpot!
But anyway. There you have:
2279
P0134
U1208
C1141
C1146
U1118 (two times)
E118
U2005
U1213
5FF

After reading I try to erase all, but all was not possible.
There was left:
2279
P0134
U1208
5FF

Also I think battery is not the best any more.

[GiveMeABreak]

There's too many codes for me to look at with the time I have this morning as I have to go out. I will take a look later for you.

[Sami_R]

Thanks, Marc!

I will also read codes again after I have charged the battery full. It is definitely weak. About 12.0 volts after night. That is first thing I will replace.

[GiveMeABreak]

Yes, a lot of the electrical faults can be down to a weak battery and that is the first thing I was going to suggest.

P2279 is to do with the 'Air pressure in air intake splitter inconsistent with throttle angle of motorised throttle body'. But I'll have more info later.

[GiveMeABreak]

Sami, I need you to confirm one thing for me as it makes a big difference.

On your Bosch engine ECU, there is a label stuck on it. I need to know whether you have a MED17.4.2 or a MED 17.4. This is where it will tell you:

The reason being that the fault codes are specific to the version and will contain information not relevant to each other, so as I don't want to be giving you inaccurate info I need you to confirm please.

[Sami_R]

Hi Marc, thank you for helping me.

I will check the ECU tomorrow. The label is maybe under side, so I have to remove it to look.
Top side is only label which shows number 8315378718 and word TRACELABEL.

I have now put the new battery to the car and done BSI reset. No difference.
Error codes I have also read again. Same codes as fist time but no C1141.

[Sami_R]

Fuses were also fine.

[GiveMeABreak]

Ok so if you can find the version that would be great then I can take a look at the codes.

[Sami_R]

Hi Marc,

I checked the ECU version. It is 17.4

[GiveMeABreak]

Ok, so these are the fault descriptors for the remaining faults:

Fault Code:	P2279
Description of Fault:	Air intake flow fault: Coherence. Air leak detected in the intake duct (lack of coherence between the information supplied by the inlet air pressure sensor and the motorised throttle opening position): The adaptation offset exceeds the threshold of 12 kg/h and the correction exceeds the threshold of 0,96 for more than 5 seconds. Conditions of activation of the diagnostics The following conditions have to be met: - Engine management ECU in main triggering phase. - The programming between the inlet pressure sensor and the motorised throttle housing position is active. - The value measured by the inlet pressure sensor is valid.
Conditions for Fault to clear:	The adaptation offset is below the threshold of 12 kg/h and the correction is below the threshold of 1,04 for more than 5 seconds.
Downgrade Modes whilst Fault is active:	The temperature reference value for the cooling units (controlled thermostat, coolant pump, fan assembly) fluctuates from 102,8 °C to 80,3 °C. No impact on the air quantity admitted: The adaptives compensate for the mass of air that is lost due to leaks in the inlet line.
Symptoms:	Lack of power
Suspect Areas:	Inlet air pressure sensor Motorised throttle housing

Fault Code:	P0134
Description of Fault:	Upstream oxygen sensor signal fault: No signal. Open circuit on the signal from the upstream oxygen sensor. The signals from the upstream and downstream oxygen sensors are greater than 1,2 V for more than 0,1 s (During the injection cut-off). Internal resistance of the upstream oxygen sensor greater than 40000 Ohms. Temperature of the exhaust gas higher than 600 °C. Voltage of the upstream oxygen sensor between 0,4 and 0,6 V. Voltage of the upstream oxygen sensor between 0,4 and 0,55 V (Temperature of the exhaust gas higher than 800 °C). Conditions of activation of the diagnostics The following conditions have to be met: - Battery voltage more than 11 V - engine running - Minimum temperature reached (defined in the engine ECU) - Heating of the upstream oxygen sensor active - Heating power of the upstream oxygen sensor higher than 0,2 (For more than 10 s)
Conditions for Fault to clear:	The following conditions have to be met: - Check that there are no fault codes : P0131 - P0132 - P0133 - P0134 - Voltage of the upstream oxygen sensor between 0,55 and 1,1 V or lower than 0,4 V for more than 1s. - Minimum temperature reached (defined in the engine ECU)
Downgrade Modes whilst Fault is active:	Deactivation of the richness regulation Change to open loop on the regulation of the upstream oxygen sensor If the fuel tank is on minimum level: Invalid "actual torque", "engine torque losses", "torque requested by the driver before processing", "torque requested by the driver after processing" and "torque anticipated after processing" information sent on the CAN. Imprecise engine torque information sent on the CAN
Symptoms:	Emissions outside the norms Unstable idling
Suspect Areas:	Upstream oxygen sensor Electrical harness

Fault Code:	U1208
Description of Fault:	No communication with the engine management ECU fault: Data invalid. Description of the diagnostics: Possibility 1 - The time for recording the fault code is 500 milliseconds - The clutch pedal sensor values sent by the engine management ECU are not coherent with those of the ESP ECU Possibility 2 - The time for recording the fault code is 500 milliseconds - The datastreams from the engine management ECU are not valid Possibility 3 - The time for recording the fault code is 500 milliseconds - The accelerator pedal sensor values sent by the engine management ECU are not valid. Conditions of activation of the diagnostics: Ignition switched on
Conditions for Fault to clear:	Possibility 1 - Clutch pedal sensor values sent by the engine ECU coherent with those of the ESP ECU Possibility 2 - The datastreams from the engine management ECU are valid Possibility 3 - The accelerator pedal sensor values sent by the engine management ECU are valid
Downgrade Modes whilst Fault is active:	Possibility 1 - The anti-lock braking system (ABS) function switches to down-grade mode - Immediate cutting of all the speed control functions (Electronic stability control (ESP)) Possibility 2 - The anti-lock braking system (ABS) function switches to down-grade mode - Immediate cutting of all the speed control functions (Electronic stability control (ESP)) - Hill start assistance function inactive - Switching of the electric parking brake to manual mode Possibility 3 - The regulation functions remain active - Hill start assistance function inactive - Switching of the electric parking brake to manual mode
Symptoms:	Lighting of the ABS and ESP warning lamps
Suspect Areas:	Connectors CAN network ESP ECU

[Sami_R]

Thanks Marc! You are very kind to provide all that information!

I’ll look at this list more carefully during the night.

In meantime I was double checking things and found that the fuse behind the battery was broken after all. So that’s why hydraulic pump is not working.