Circuit/System Testing
- Ignition OFF, disconnect the harness connector of the knock (KS) sensor.
- Ignition ON, connect a test lamp between the signal circuit of the KS and the negative battery terminal.
- If the test lamp illuminates, test the signal circuit for a short to voltage. If the circuits/connections test normal, replace the ECM.
- Ignition ON, connect a test lamp between the signal circuit of the KS and the positive battery terminal.
- If the test lamp illuminates, test the signal circuit for a short to ground. If the circuits/connections test normal, replace the ECM.
- Ignition OFF, connect a DMM between the signal circuit and the low reference circuit.
- Test for 90-110 K ohms between the signal circuit and the low reference circuit of the KS.
- If the resistance is not within the specified range, test the circuits for an open/high resistance. If the circuits/connections test normal, replace the ECM.
- If all circuits/connections test normal, replace the KS sensor.
IMPORTANT:
If the knock sensor lead is damaged in any way, replace the knock sensor.