Citroen C4GP 2L petrol fault codes

[Craigie]

I have a 2007 C4GP 2L petrol 78000 miles.
Having a recurring fault code which happens intermittently with no difference in driving. Occasionally when idling there's a bit of hunting/chugging but very occasionally
Fault codes are P0170 and P0172
Could these be the coil pack or something else? Any help would be appreciated

[GiveMeABreak]

Those errors relate to the fuel injection.

P0170: Mixture regulation: Coherence. Basically the fuel trim is out - in this case too rich - see the other fault below:

P0172: Mixture regulation: High stop. The fuel trim is too high. The engine ECU reads parameters and data to adjust the fuel trim which includes the MAF / MAP / Oxygen Sensors to measure exhaust gasses.

So in this case the mixture is too fuel rich with not enough oxygen.

Common culprits could be in no particular order: Oxygen sensor, fuel regulator, worn plugs, a dirty MAF sensor.

[Hagrid]

Hi all. My first ever post! I'm posting in this thread because it relates to the P0170 fault code.

I've had some Berlingos but now I've got a 2008 7-seat C4GP 1.8L VTR+.
Low miles for age, about 66k.
VIN: VF7**************[VIN obfuscated, can be read by forum staff]

Central display message: de-pollution system faulty.

Code reader (Creader 319): only one fault:
P0170 - the reader describes it as "fuel trim bank 1".
Code reader O2 readings:
Bank 1: fail 0.530 volts
Bank 2: ditto.

Reset fault, de-pollution message disappears. No fault codes.
O2 readings:
Bank 1: pass 0 volts
Bank 2: fail 0.530 volts.

The reader cannot 'fix' the 2nd sensor despite several clearing attempts.

But the fault code referred to bank 1, and when the bank 1 sensor was 'fixed' the fault code disappeared.
So why is there no fault code for bank 2 which cannot be 'fixed'??
Which one is really faulty?

I know almost nothing about O2 sensors, I guess they are in the exhaust manifold and pipe?

I can't do the work as I'm ancient and unfit (I don't like being horizontal and awake at the same time), so what does a sensor cost, what part no. should I order, could a mobile mech do the work, and what would be a reasonable fee? I'll book a basic service at the same time, in case that has a bearing on your advice.

Could there be other issues hiding unnoticed behind this one?

Any advice very welcome!

[myglaren]

Hi all. My first ever post! I'm posting in this thread because it relates to the P0170 fault code.

You have 25 previous posts, from 2020.

[RichardW]

Bank 1 / 2 is a bit misleading since this is an inline 4, and there's only 1 bank! It may be that there are 2 sensors, one upstream and one downstream of the cat, not sure. You probably need to get better diagnostics and some tests to see what is going on before you condemn the O2 sensor.

[GiveMeABreak]

Unfortunately I don't have any significant info on this engine - these older petrols have limited fault data, as all I'm showing is the perfectly useless:

P0170: Fuel injection: Malfunction

Sorry.

[Hagrid]

You have 25 previous posts, from 2020.

oh dear - old age and stuff!

[myglaren]

[Hagrid]

Bank 1 / 2 is a bit misleading since this is an inline 4, and there's only 1 bank! It may be that there are 2 sensors, one upstream and one downstream of the cat, not sure. You probably need to get better diagnostics and some tests to see what is going on before you condemn the O2 sensor.

Thanks Marc and Richard for trying.

I suspect the bank thing is down to the reader - it seems to be fine with US vehs but is known for not being much use with German cars - so maybe French ones too. Certainly, it couldn't read my VIN and some other features came up as 'not supported by veh' - or maybe veh/reader incompatibility... is there an American version of Frangais?