C8 - Haunted Lights, Rear Wiper, Washer Fluid etc.

[MikeRatcliffe]

I have a 2003 Diesel C8 and over the last few months it was displaying a passenger airbag fault but because the fix is likely expensive (I checked the usual suspects) I left it.

A couple of weeks ago lost it's pairing with my key so I bought new batteries (fob and car) and re-paired they key.

Then yesterday... things happened in this order:

1. Key pairing lost.
2. Unlocked driver's door manually with key.
3. Opened driver's door.
4. Alarm started.
5. Turned key in ignition but the immobilizer was active.
6. Tried pairing the key but no joy.
7. Disconnected batter negative... was surprised the alarm is on a backup battery.

At this point I gave up and decided to wait until the alarm battery had run down.

The next time I tried again but the car seems to be "haunted":

1. Reconnected battery.
2. Turned the ignition on.
3. Paired the key.
4. Started the engine.
5. Headlights started to flash like they were trying to communicate in Morse code (I enabled daylight running lights about a year back if that helps).
6. Washer fluid was spraying out in pulses.
7. Horn started beeping randomly.
8. Back wiper started even though it should be off.

I ran the engine for a while to charge the battery a little.

When I switched the engine off the key pairing was lost so I was back where I was the day before with the alarm going off and no way to disable it.

Does anybody recognize these symptoms?

[Hell Razor5543]

That might suggest the main battery is becoming weak. C series Citroens (because they have a lot of electronics) are sensitive to failing batteries, and can throw up all sorts of faults when the battery gives up.

[C5petrol155]

I had one C5 2hdi with the same issue. The private mechanic checked it and told me the cable is broken but the airbag works. Then I crashed and the car opened all airbags. So the mechanic was right. Now I've got C5 2hdi with the same issue. The same private mechanic told me the cable is broken but the airbags work. So I don't worry.

[GiveMeABreak]

It sounds like the comms unit (steering control module) under the steering wheel. This unit is responsible for the lighting and and the handshaking of the transponder signals to and from the BSI (hence your starting and alarm issues). I suspect if you have checked you have a fully charged battery and have tried the BSI reset here:

BSI Reset / Battery Disconnect / Reconnect Procedure

...then you might need to look at the module.

[MikeRatcliffe]

Yep, already replaced the car battery, fob battery and tried a few BSI resets.

I thought it might be the comms unit, thanks.

Now I just need to work out how to fix it

[GiveMeABreak]

It's really a replacement - not a fixable thing, as it's unlikely to be a stalk issue. Get it diagnosed with Lexia, pop any codes up here (although not all Comms units provide fault codes) and the VIN, so we can look the fault codes up and provide you with the correct part number as these are all different and vehicle-specific units.

[MikeRatcliffe]

It's really a replacement - not a fixable thing, as it's unlikely to be a stalk issue. Get it diagnosed with Lexia, pop any codes up here (although not all Comms units provide fault codes) and the VIN, so we can look the fault codes up and provide you with the correct part number as these are all different and vehicle-specific units.

To be honest I didn't realize I would be able to use my Lexia with the car going all Christine on me.