Citroen C4 diesel showing lots of errors and stalling

[snozwoz]

Hello

I have a Citroen C4 diesel auto 2015. Car started giving issues recently.

Cars starts and runs fine, but when I start driving I will get engine lights and warnings, a common one I see is AGR/EGR errors, engine fault, STOP etc. I also find these issues are more likely present when under load such as driving up a hill and throttle is pressed down - it can also stall, and releasing throttle sometimes allows it to recover.

I took it to garage and they found many fault codes. They concluded the AGR battery was giving low voltage, which surprised me as it was just 2 years old and appeared to work perfectly, but fortunately, I was able to get it replaced under the battery warranty.

However, I still have the issues - so it cant be the battery.

From the error codes, the ones related to engine are
* P1AA2 - voltage retaining device
* P1199 - InCoherence on the reserve fuel pressure
* P0087 pressure measured in injector rail lower than setting.

In braking, it does not mention AGR/EGR but does list one code
* C2391 engine torque not cleared fault

There are many other error codes, mostly marked as 'intermittent' as are the ones above.

Love some ideas on what it could be, thanks

[RichardW]

The brake codes are a red herring - these come on because the engine ECU is setting a code. Since 2 are related to fuel pressure, I would chuck a new fuel filter in it - this fixes the vast majority of low fuel pressure codes. The voltage code may or may not be important; fix the fuel pressure and take it from there.

[snozwoz]

Hi, thanks for responding. This is a small update from me. The garage (Mr. Clutch) insisted the battery was at fault. Fortunately, the battery was under warranty with Halfords, and they were very good and agreed to replace it free of change even though their tests showed no issues. This did not solve the issue; I have now taken it back to the garage (Mr clutch) for diagnostics again. The fault codes have changed a little, the garage was positive about that, the ones above cleared. There are still many, but the important and frequent ones in my Citroen diesel are now:

p0087 = pressure measured in injector rail
U1213 = communication fault with the ABS/ESP system (repeated multiple times)
c0037 = Rear Left Wheel Speed Sensor

Only p0087 is common to both diagnostics, whilst u1213 was not in the first; the dashboard did show this error.

Also, driving back from the garage after the codes cleared, I had no issue until I drove up a hill, where the engine started stalling, pulling back on the throttle allowed the engine to recover, followed by many error messages on the dashboard.

I like your suggestion, RichardW. I'll get the fuel filter replaced—it hasn't been changed in some time.

These issues also started after filling the car with fuel. I hope it's not a dirty fill. It's going to take some time to consume it. Maybe I'll buy the premium diesel next time if it's recommended and compatible with my car. i also wonder if I should go to a different garage with better engineers if these issues persist after the fuel filter change. Either way I'll report back here in case others suffer similar codes.

EDIT: I just ordered some Wynn's Diesel Injector Cleaner too, ill get fuel filter replaced and add this additive too.

[snozwoz]

I just drove the car foot to the floor up a steep hill without stalling - which was impossible earlier in the week. The car is booked on Friday for a fuel filter replacement, so without this being done, I can only assume improvement is a result of Wynn's diesel injector cleaner. If so, I'm impressed; I thought it was a gimmick, yet worth a try for the £5 it cost. The car is undoubtedly driving better.

I still have the service light on, no engine lights now, so I'll see what the garage makes of that. I'll also still have the fuel filter changed.

(edit) SOLVED —The service light turned out to be a bulb. So, although I am still having the fuel filter replaced, as good practice, all these error codes were resolved by combining battery replacement and using Wynn's diesel injector cleaner.

[snozwoz]

update, some problems solves, others not - its intermittent. Engine is better, but dashboard is still lighting up with errors occasionally - think I need auto electrician.

[PaulC5]

If you are not going to use a Citroen dealer make sure whoever you choose has Citroen diagnostic equipment.

[snozwoz]

for sure, I get in and the dashboard lights up with ESG/ASR error, hand brake error, ABS error, and many more - yet the car is driving fine now. Each time I got diagnostic check, many of the codes change between checks. I guess it is one faulty thing causing many errors, or a wiring issue even - think I need a garage with more capable mechanic or electrician, not got around to it yet, but need to make some calls. Damn this car.. I mean, it's a workhorse, but when it goes wrong, it's complex stuff.