Ecu Reset Procedure

[Guest Citroen CT]

hello all i work in the dealer network and upon reading alot of the posts you may find this info useful

 

How to reset all ecu's

 

this procedure is called a power latch

 

firstly turn on the ignition not engine running,

open bonnet remove battery positive lead and then turn off ignition.

then touch the positive lead to earth,this powers down all ecus and resets erasing intermittent faults in the process.then reconnect the battery lead.

if the vehicle doesnt start straight away leave the ignition on for 2-3 mins as it has gone into anti scanning mode.

 

IMPORTANT PLEASE READ CAREFULLY

upon starting the vehicle DO NOT TOUCH THE THROTTLE allow vehicle to idle until cooling fans cut in to allow the engine ecu to reset correctly and reprogramme the learning curve,then drive in all gears upto 4,000 rpm accellerating steadily.

 

as stated this resets all ecus so any electrical faults caused by conflict errors in programming will be erased and fixed.if the fault is still evident there is a problem that will need further diagnosis

[druid]

Anyone know if this is safe?

[paul.h]

I have never tried it and would be reluctant to do so. The original poster is no longer a member of the forum so we can not check on the validity of the method quoted or even the background of the poster. If you search the internet there are many methods quoted to reset the bsi and we have one pinned in the C5 Technical section. Usually if disconnecting the battery you remove the ignition key and wait for the bsi to shut down to ensure there are no odd electrical problems caused. The procedure I follow is this:

 

20. Odd electrical problems caused by wrong battery disconnection procedure.

If you need to disconnect the battery and not do a BSI reset procedure, I have found the following has not given me any problems on a 2004 and 2007 C5 and a 2003 C3:

- remove the ignition key from the car

- open the bonnet

- wait a few minutes for the BSI to shut down

- disconnect the battery negative terminal

 

When reconnecting

- ignition key out of the car

- reconnect the battery

- wait a few minutes

- insert the key in the ignition and wait a minute

- turn the key to the first position and wait a minute

- turn the key so the dash lights come on and wait a minute

- start the engine

- take the windows down and up to reset the anti pinch

- reset the clock (and radio on the C3).

[druid]

Thanks Paul

I did wonder if this was any good as it seemed a bit strange.

I wanted to clear my ecu etc to see if that would help with my fuel gauge problem. I was told to disconnect the positive lead for 15mins and that would clear everything, well I did that and it cleared nothing not even the radio stations.

I guess I should do the negative lead instead of the positive one.

[druid]

Also what is the BSI reset?

[paul.h]

There is a bsi reset procedure here:

http://www.citroen-owners-club.co.uk/citroen/topic/15093-bsi-reset/

[druid]

Thanks is it the same for the C4?

[coastline taxis]

in one of your fuse boxes on the car there will be a fuse marked SH or sometimes its a odd looking fuse with the metal strip on the outside either way its the only one of its kind in the fuse box. This is a shunt fuse switch ignition off and remove key wait 5 mins then pull this fuse and go and have a cup of tea. Replace the fuse and then just wait till the plimp key works the central locking then start the car and take it for a 30 min drive trying to use motorways, hills and normal streets to drive down. this will reset your ecu and relearn the adaptive drive cycle,s