PGM-FI System

DTC Troubleshooting (cont'd)

11-531  

DTC 23: Knock Sensor Circuit Malfunction

  1. Reset the ECM/PCM (see page 11-468).
  2. Turn the ignition switch ON (II).

Is the MIL on and does it indicated DTC 23?

YES

- Go to step 5.

NO

- Go to step 3.


  1. Start the engine at 3,000 rpm (min-1) with no load (in Park or neutral) until the radiator fan comes on, then let it idle.
  2. Hold the engine at 3,000-4,000 rpm (min-1) for at least 60 seconds.

Is the MIL on and does it indicated DTC 23?

YES

- Go to step 11.

NO

- Intermittent failure, system is OK at this time. Check for poor connections or loose wires at the knock sensor and at the ECM/PCM.


  1. Turn the ignition switch OFF.
  2. Disconnect ECM/PCM connector A (31P).
  3. Check for continuity between ECM/PCM connector terminals A8 and A20.

ECM/PCM CONNECTOR A (31P)

Wire side of female terminals

Is there continuity?

YES

- Substitute a known-good ECM/PCM and recheck. If symptom/indication goes away, replace the original ECM/PCM.

NO

- Go to step 8.


  1. Disconnect the knock sensor 3P connector.
  2. Connect the knock sensor 3P connector terminals No. 2 and No. 3 with a jumper wire.

KNOCK SENSOR 3P CONNECTOR

Wire side of female terminals

  1. Check for continuity between ECM/PCM connector terminals A8 and A20.

ECM/PCM CONNECTOR A (31P)

Wire side of female terminals

Is there continuity?

YES

- Replace the knock sensor.

NO

- Repair open in the wire between the ECM/PCM (A8, A20) and the knock sensor.