Ground Circuit Inspection

Ignition "OFF"
Disconnect Knock sensor and ECM connectors
Measure resistance between terminals 2 of the sensor harness connector and 21 of the ECM harness connector
Specification : Approx. 0Ω
Is resistance within the specification?
YES
- Go to "SIGNAL CIRCUIT INSPECTION " procedure
NO
- Check for an open in ground circuit. Repair as necessary and go to "VERIFICATION OF VEHICLE REPAIR " procedure