electrical problems with c3 2003

Thank you for this useful group.
i already had many problems in my c3, i changed ECU and the fuse box near battery, also the japanese unit that controls hydraulic steering... i sent the car to a garage to repair motor joints and change (colasse) water pump belts.... when i went there to take it i saw an Airbag error this is the first time i see it. maybe they caused a short circuit when they were working or when they were connecting the battery after removing it. the problems im having: airbag error with trembling headlights (on and off light fast) and sometimes check engine light comes on and fuel pump wont deliver fuel as it should so the car becomes too slow.... i turn ignition off for some time then on the problem disappears... what do you suggest? i am thisking about changing the com 2000 unit behind steering wheel but is this affecting the fuel pump or only the airbag and lights? Thank you in advance

Hi mcles00, welcome to the forum

mcles00 wrote:i already had many problems in my c3, i changed ECU and the fuse box near battery,

What error or problems did you get that led you to change the ECU and the engine fuse box - BSM?

mcles00 wrote: also the japanese unit that controls hydraulic steering.

The electric power steering ECU. What problem did you have that led you to change this? Were you also advided to change the power steering motor at the same time?

mcles00 wrote:i sent the car to a garage to repair motor joints and change (colasse) water pump belts.... when i went there to take it i saw an Airbag error this is the first time i see it. maybe they caused a short circuit when they were working or when they were connecting the battery after removing it

When the cambelt is changed its not likely that the Airbag system is going to be damaged. I don't think the garage, while doing the belts, would have done anything to the air bag/seat belt system.

mcles00 wrote:the problems im having: airbag error with trembling headlights (on and off light fast) and sometimes check engine light comes on and fuel pump wont deliver fuel as it should so the car becomes too slow....

Read the errors (you will have several) with the Citroen diagnostic tool like this one on eBay and a laptop.

There is a topic covering lexia https://citroenc3owners.com/citroen-c3-t ... -t655.html

Both the COM2000/BSI problem - headlights and the AIRBAG error will require lexia and not OBD2 to diagnose. Lexia will also help you with the engine running, but so can OBD2 (see the link above).

mcles00 wrote:what do you suggest?

Diagnose the fault with the right tools otherwise you will just keep changing parts and more parts.

mcles00 wrote:i am thisking about changing the com 2000 unit behind steering wheel but is this affecting the fuel pump or only the airbag and lights?

COM2000 has the connection to the drivers airbag, so it may have an effect on airbag warning. I don't see how the COM2000 would affect the fuel pump, but you don't know its a fault with the pump?
COM2000 and BSI (cabin fuse box) have a hand in the lights.

Thank you for your information, AUTEL scanner gave error code for airbag problem P2F4A as permanent fault, i checked autodata theres no such fault, do you know about it? i will take it to a pro repair shop where they have lexia scanner for better analysis.... also im having weird problem sometimes the fan stops running suddenly!!! i remove its plug then connect it it works! what is this problem related to??

mcles00 wrote:AUTEL scanner gave error code for airbag problem P2F4A as permanent fault,

If you have changed BSI module and not configured it with Lexia tool you may see an error like this.

I have seen these odd looking codes, similar to P2F4A as permanent fault when configuration is incorrect in the BSI module because it doesn't match exactly the specification of the car. Its common when upgrading software in the BSI, but you would also get this when swapping a BSI from a different car.

Or you could have a faulty airbag ecu? Lexia will tell you what's going on.

Hello guys,

i took the car to the dealer garage in Beirut, after 3 days there they told me that the computer doesnt need programation or something like that.... they told me that the ecu(computer of the car) i changed lately is for an automatic citroen with ABS, my citroen is manual without ABS so i have to change it... i asked them to put my old computer (*original one that came with the car, i kept it with me after change) and scan, when they put the old computer they started working correctly, electric problems solved were:
1- This car needs double headed spark plugs so they changed my champion one head sparks
2- they also changed the Coil (bobine d'allumage) not because its not working, but because its not original so it may affect electricity.
(its very important to check these 2 if you are having electric problems)
3- they checked the wires and put new ground wire.
4- changed oil filter and a small part behind it.
5- after all this i tried the car, the speed meter stopped on 0 and the car turned off! i returnned to the garage, they rescanned and founed that the (speed sensor which is located on the vitesse behind motor) is faulty, so i asked them to change it with new one, and this solved the problem! (its a very common problem, dont change this parts with used one get the original new one from dealer).

All this costed about 400$ and its better than changing parts randomly... i hope this info will help many to solve common problems...

Best regards :0)

C3driver52 wrote:i hope this info will help many to solve common problems...

I am sure it will. Many thanks for the detailed information