Knock Sensor: Testing and Inspection

Knock Sensor Testing:

NOTE: This test requires use of Mazda Self-Diagnosis Tester (SST #49 H018 9A1) or equivalent aftermarket "Scan" tool.

1. Warm engine to operating temperature and run at idle.
2. Connector SST to check connector (Green: 6-pin).
3. Tap engine hanger lightly with a plastic hammer and ensure that monitor lamp does not illuminate.
4. Ground test connector (Green: 1-pin).
5. Tap engine hanger again and verify that monitor lamp illuminates for approximately 0.5 second.
6. Remove test connector jumper wire.
7. If not as specified, replace knock sensor.

Knock sensor signal is input at ECU terminal 2M. Because voltage is very low whether knock is occurring or not, terminal voltage will always be approximately 0V.