Operation CHARM: Car repair manuals for everyone.

Programming and Relearning



61 20 908 Performing battery "power reset" (for programming/coding control unit(s))







IMPORTANT: Observe safety instructions for handling vehicle battery.







The following steps must be carried out for a "power reset":
- Switch off and disconnect battery charger
- Switch off ignition
Cars with ignition key: Turn ignition key to 0 position
Cars with identification sensor:
Remove identification sensor from slot
Cars with comfort access system:
Make sure terminal is in 0 position
- Disconnect battery negative terminal
- Reconnect battery negative terminal (to ensure bus activity)
- Waiting time (5-10 seconds)
- Disconnect battery negative terminal
- Waiting time (1 minute)
- Connect battery negative terminal and tighten, tightening torque 61 21 1AZ
- Connect and switch on battery charger
- Switch ignition on