Car not detecting reverse

Hello,

I have a 2011 C3. The aircon stopped working, tried the BSI reset, did not solve the aircon problem but now when i put the car in reverse the reverse lights dont come on and the parking sensor system doesnt engage on the NAV screen. Tried another BSI reset but did not help.

Any other things i can try before i bring it to the garage?

Thanks!

Not that familiar with the more modern C3's but being a manual transmission, there will be a switch on the gearbox that indicates the transmission is in reverse. Either the switch is faulty or whatever actuates the switch is worn or needs adjustment.

Ozvtr wrote: ↑Wed May 31, 2023 10:20 pm Not that familiar with the more modern C3's but being a manual transmission, there will be a switch on the gearbox that indicates the transmission is in reverse. Either the switch is faulty or whatever actuates the switch is worn or needs adjustment.

Thanks for the reply, it just seems a bit weird that the switch, alignment would go wrong after performing the BSI reset, im guessing its more a software thing then a hardware thing.

Ok. Looks like the switch on the gearbox is connected to the BSM (engine bay fusebox) and the BSM transmits a reverse light 'on' request via the CAN BUS to the BSI.
The parking sensor module is also connected to the BSI.
If it's the BSI, it's some sort of firmware fowl up.
Could also be the BSM for the same reason.
If it's not the gearbox switch then I have some good news and some bad news. The good news is that there cant be anything broken. The bad news is I don't know how to fix it.
Pin 13 of the grey 28 pin connector on the BSM should have continuity to ground when the gearbox is in reverse.

What steps did you take to do a BSI reset?

Ozvtr wrote: ↑Thu Jun 01, 2023 8:10 am Ok. Looks like the switch on the gearbox is connected to the BSM (engine bay fusebox) and the BSM transmits a reverse light 'on' request via the CAN BUS to the BSI.
The parking sensor module is also connected to the BSI.
If it's the BSI, it's some sort of firmware fowl up.
Could also be the BSM for the same reason.
If it's not the gearbox switch then I have some good news and some bad news. The good news is that there cant be anything broken. The bad news is I don't know how to fix it.
Pin 13 of the grey 28 pin connector on the BSM should have continuity to ground when the gearbox is in reverse.

What steps did you take to do a BSI reset?

I'll check the pins later when im at home but this is the procedure:

https://frenchcarforum.co.uk/forum/view ... hp?t=61997

Thanks for the help untill now, i measured the pin and the switch is working correctly, so only thing left is a software/bsi problem. Will have to find somebody in the netherlands that can connect it to diagbox/lexia then.

Ive tried connected a Carly OBD2 but it says ECU not responding...

greetoz wrote: ↑Wed Jun 07, 2023 3:12 pm Ive tried connected a Carly OBD2 but it says ECU not responding...

Only top end scan tools can read the ECU's. The OBDII protocol only deals with problems DIRECTLY related to anti-pollution faults. So it will only deal with a few engine problems and that's it.

I'm sorry but I have no idea. I'm not that familiar with the newer C3's.
The only thing that I can suggest is if you head over to "The french car forum", join up, state your case and VIN. They have access to Citroen's data base of known fault's. Citroen might know of this fault and have a fix?

Apart from suggesting a faulty BSM, I've got nothing...sorry.

To be honest with you I find it hard to believe that this is a firmware 'bug'. But that's just my opinion.

Just thought of something. Have you tried disconnecting the switch connector and shorting it to ground?
Short pin 1 to ground, see if there is change. Short pin 1 to pin 2, try again. Pin 2 is ground but try an independent ground as well.
Just clutching at straws. Switch might have enough resistance to register on multimeter but not to BSM?