Knock Sensor: Testing and Inspection
MALFUNCTION CODEIf the engine "pings" excessively and base timing is okay, check the on-board diagnostic system. A faulty knock sensor or knock control unit will set malfunction code 05. Refer to DIAGNOSTIC CHARTS.
KNOCK CONTROL SYSTEM TEST
Knock Control System Testing:
1. Connect Mazda Self-Diagnosis Checker (SST #49 H018 9A1) or equivalent aftermarket "Scan" tool to check connector.
2. Ground test connector with a jumper wire.
3. Turn ignition switch "ON."
4. Tap right engine hanger (drive belt side) with hammer and check that SST monitor lamp flashes.
5. If lamp does not flash, connect a known good knock sensor to wiring harness and provide sensor with a good ground.
6. Repeat tapping procedure. If lamp now flashes, original sensor is defective and should be replaced.
7. If lamp still does not flash, knock control unit may be defective. Ensure that wiring and harness connections are in good condition before replacing control unit.
Knock control unit input voltage can be checked at ECU terminal 2M. With ignition "ON" and engine running at idle, voltage should be 3.3 - 5.0V. When knocking occurs, voltage should be 1.3 - 2.6V.