Necessary preliminary tasks:
Unlock connector (1) and remove.
Release bolt (2) on knock sensor.
Remove knock sensor for 3rd and 4th cylinders.
Installation note:
Clean contact surface of knock sensor on engine block.
NOTE: Reassemble the vehicle.
Check stored fault message.
Delete fault memory.
BMW X3 Service & Repair Manual > Troubleshooting: Instructions for welding work (overload protection of control units)
CAUTION: Follow instructions for body repairs.
When performing welding work on installed control units, to avoid any defects in the electronic control units,
observe the following steps:
Observe instructions for disconnecting and connecting battery.
Detach terminal of battery negative l ...