Knock Sensor: Testing and Inspection

INSPECTION

NOTE: The Knock Sensor (KS) can only be tested as a system and its failure will be determined by a process of elimination.

1. Turn ignition switch off.
2. Install the test harness to the engine wire harness only, not to the Programmed Fuel Injection Electronic Control Module (PGM-FI ECM). Disconnect the two pin connector at the Knock Sensor.

Knock Sensor Terminal Identification:

PGM-FI ECM Connector Description And Wire Location:

3. Check for continuity between the D3 terminal and chassis ground. there should be no continuity. (If continuity exists, inspect/repair short in RED/BLUE wire between ECM D3 and the knock sensor connector).
4. Check for continuity of the RED/BLUE wire between the D3 terminal and the two pin connector at the Knock Sensor. there should be continuity. (If no continuity exists, inspect/repair open in RED/BLUE wire).
5. Substitute a known good Knock Sensor. Warm engine up to operating temperature (cooling fan comes on). Hold engine at 3000-4000 rpm for approx. 10 seconds with trans in neutral. Check to see if DTC 23 or symptom still exist. If DTC indication/symptom goes away, replace Knock sensor. If DTC indication/symptom exists, substitute a known good PGM-FI ECM and retest.