C4 Grand Picasso intermittent engine fault

[stevehurombe]

Hi,
The car is a 2015, 2L Diesel, automatic, exclusive. ~90K miles.

Earlier in the year the car developed a permanent engine fault and it went into limp home mode. That turned out to be a fault on fuel injector 4, which was replaced at the main dealer. The local French car specialist lacks the computer smarts to diagnose anything.

A couple of months later it developed an intermittent condition with similar behaviour. Unfortunately when the car gets to the main dealer there are no fault codes (according to them) that can tell them what the issue is.

It's been doing this all year now, mainly once or twice on a long run, it's fine in normal day to day driving. It mostly happens while cruising on the motorway, on the flat do nothing particularly out of the ordinary. Switching it off and on again usually resolves the issue.

There are no codes to see.

I suspect they replacement fuel injector is faulty, but how do I move this forward?

I am IT literate so I was wondering of there was anything I could plug into the computer to monitor with my laptop to try and capture something?

Thanks in advance.

Steve

[Hell Razor5543]

Hi, and to the Forum. Yes, there is equipment you can get. It is a clone of the (unavailable to the public) equipment that the PSA Group uses (so not much in the way of instruction manuals). It is known as Lexia/Diagbox. There are various versions available, but you must make sure it has the full opto-coupler set, as some of the cheaper clones had a reduced set, and may not work with certain vehicles. Easy Diagnostics is a supplier that several Forum members have used (I am one of them), and the Forum is NOT linked to them in any way. They regularly sell out (which could be interpreted as a sign of the quality).

https://www.easydiagnostics.co.uk/shop

Wherever you get it from make sure to take each step very carefully and take accurate notes of any settings before you change them, as there is no "Undo" function. If you get them badly wrong you could 'brick' an ECU, taking the vehicle off the road.

[stevehurombe]

Thanks James. I'll have a poke around.

A neighbour had a bluetooth OBD reader can I got a code out using EasyOBD of C0700. Needless to say it's a custom Citroen code.

I'll see what they can make of that.

Will this tech work with EV's? I'm wondering if this tooling would be a good long term investment.

[stevehurombe]

Hi,

The fault is now permanent and the garage are saying that it's the particulate filter that needs replacing. Sounds fishy to me, but what do I know? Is that a cause or an effect?

They claimed they did a regen in August, but that's news to me.

Cheers,
Steve

[RichardW]

I would expect a message for risk of filter blocking if that was the case. If the engine management light is on then even a cheap reader should be able to pull the OBD code to give a pointer.

[stevehurombe]

I am getting that message too now, but only when the fault went permanent. What's confusing me is that if this was the root cause wouldn't that have been the first message? Or am I reading too much into the computer's ability to diagnose issues?