Inspection Procedure

DTC 52 - Knock Sensor Signal

INSPECTION PROCEDURE
1. Check continuity between terminal KNK of engine control module connector and body ground.
- Turn up the floor mat on the passenger side.
- Disconnect the engine control module (ECM) connector.




- Measure resistance between terminal KNK of engine control module connector and body ground.
OK if: Resistance is 1 Mega Ohm or higher.
- If OK proceed to step 3.
- If not OK proceed to step 2.

2. Check knock sensor.
- Disconnect knock sensor connector.




- Measure resistance between the knock sensor terminal and body.
OK if: Resistance is 1 Mega Ohm or higher.
- If OK proceed to step 3.
- If not OK Replace knock sensor.

3. Check for open and short in harness and connector between engine control module and knock sensor.
- If OK proceed to step 4.
- If not OK repair or replace harness or connector.

4. Does malfunction disappear when a good knock sensor is installed?
- If Yes replace knock sensor.
- If NO Check and replace ECM.

INSPECTION USING OSCILLOSCOPE




With the engine racing (4,000 rpm) measure waveform between terminal KNK of engine control module and body ground. The correct waveform appears as shown in the image.




Spread the time on the horizontal axis, and confirm that period of the wave is 123 microseconds (Normal mode vibration frequency of knock sensor: 8.1 KHz). If normal mode vibration frequency is not 8.1 KHz, the sensor is malfunctioning.
NOTICE: A set driving pattern is necessary for detection this Trouble Code. Be sure to follow that pattern when performing a test drive to confirm repair. For a description of the prescribed driving pattern, refer to Knock Sensor Signal Description.
Description