Error P1A9C stop start accumulator

[MelC4]

Hello,

I am have this problem with my C4, i have changed the battery and the capacitor accumulator and the error is still there is there a fix for this problem.

Kind regards
Mel Wright"

[GiveMeABreak]

This can generally result in several solutions:

1) Check the tightness of the cable nuts on the central voltage maintaining device.
2) You need to use the specific guided procedure "Replacement of the energy storage battery or of the voltage maintaining device" using Diagbox.

[MelC4]

Okay I will try it out all tips welcome
Cheers thank you.

[MelC4]

Hi I managed to clear the error P1A9C and now there is error U1134 any ideas how to fix this 1.

[thangviet]

Hi I managed to clear the error P1A9C and now there is error U1134 any ideas how to fix this 1.

Out of curiousity, how did you manage to clear/fix the P1A9C and are you getting any other errors aside from U1134 (LIN network issue?)

[MelC4]

Hi a mechanic with his Diagbox tool registered the replacement stop start capacitor now I have these 2 errors U1133. & U1134.

[dennisjr2k5]

Hi, MelC4. I'm having the same problem of P1A9C, how did you clear the error? thanks

[MelC4]

Hi sorry for the late reply, i replaced the stop start capacitor.

[GiveMeABreak]

Hi a mechanic with his Diagbox tool registered the replacement stop start capacitor now I have these 2 errors U1133. & U1134.

I've only just picked this up, however as you've said you have had the Voltage Retaining Device replaced, you need to be aware that you can't just replace it. It needs programming with Lexia / Diagbox or you'll likely end up with faults. So has he properly done everything required using the diagnostic tool? There should be a guided procedure to do this. I ask this despite what you've said about him 'registering' it, but as you can see one of these faults refers to the device as absent....

Fault Code:	U1133
Description of Fault:	LIN: The reversible alternator is confirmed absent. Faults in communication between ECUs on the LIN.
Conditions for Fault to clear:	Ignition switched on
Downgrade Modes whilst Fault is active:	Automatic restarting impossible following stopping of the engine (Requires restarting of the engine using the key).
Symptoms:	Problem with automatic restarting of the internal combustion engine Absence of automatic stopping of the internal combustion engine
Suspect Areas:	Supply of the voltage retention device Reversible alternator supply Electrical harness

Fault Code:	U1134
Description of Fault:	LIN: Voltage retention device confirmed absent. Faults in communication between ECUs on the LIN.
Conditions for Fault to clear:	Ignition switched on
Downgrade Modes whilst Fault is active:	Automatic restarting impossible following stopping of the engine (Requires restarting of the engine using the ignition key). Switching on of the warning lamp and/or warning message: "SERVICE" warning lamp.
Symptoms:	Problem with automatic restarting of the internal combustion engine Absence of automatic stopping of the internal combustion engine Malfunction of the Stop and Start switch or its LED
Suspect Areas:	Supply of the voltage retention device Reversible alternator supply Electrical harness

[MelC4]

Hi Marc I did replace the stop start Ecu then that cleared the other 2 errors its 1 year now and working fine no more problems, apart from a fuel gauge registering problem this week that I have caused by topping up with 8 litres to fill the tank is there a fix for this problem it shows 2 clicks short with full tank of fuel.

[GiveMeABreak]

That issue can sometimes clear itself, but can be avoided by not filling past the 'clicks' when adding fuel.

Try allowing the tank to run down to a quarter full, then filling up to the first click only. See if that restores the gauge correctly.

[MelC4]

Ok thank you I will try that.

[dennisjr2k5]

Hi sorry for the late reply, i replaced the stop start capacitor.

It's, okay. Will try this approach, thanks a lot/

[Ibiza]

2012 Citroën C4 1.6 e-HDi (stop/start).

Engine fault repair needed + service light on.

Code: P1A9C – energy accumulator fault.

Battery is good (12.4V off, about 15V running).
Changed the IBS (battery sensor) – no change.
Code clears but comes back.
Before I change the alternator, could this be the capacitor or wiring?
What’s the proper way to test it?