ecu reset

[chavelock]

Hi I've got a 97 vw passat 1.8 20v can some one please tell me how to reset the ecu.
Lately I changed the battery and when I started the car it started hopping through the ref ( up and down ) .

Cheers craig

[Crasher]

Hello Craig and welcome. The ECU must be reset using diagnostic equipment such as VAG-COM in Basic adjustment mode 04 sub group 098 with the engine hot but not running and the ignition on, but I would recommend the throttle body is removed and cleaned first. Before the Basic Adjustment is carried out, the fault memory should be read, saved/printed and then cleared. It could even be beneficial to clear the ECU adaptations in Adaptation 10, sub group 00 as it will have learnt some adaptations running like it has been.

[chavelock]

Thanks for that.
looking at your reply to my question,
I think even after your first line I'll take in to the garage.
I thought it might have been possible by discon the batt.

Thanks again
Craig

[Crasher]

Unfortunately, disconnecting the battery is what causes the problem.