‒ Check wiring between test box and knock sensor for open circuit according to current flow diagram.
Contact 1+socket 39
Contact 2+socket 19
Wire resistance: Max. 1.5 ω
‒ Measure resistance between knock sensor contacts.
Specification ∞ω
If no wiring fault is detected:
‒ Loosen knock sensor and tighten again to 20 Nm.
‒ Carry out test drive.
During the road test the following operating conditions must be fulfilled:
‒ The coolant temperature must exceed 80 °C .
‒ When the temperature is reached, the operating conditions
Idling
Part throttle
Full throttle
Overrun
must be attained several times.
‒ At full throttle the speed must exceed 3500 rpm.
‒ Again interrogate the control unit fault memory.