Knock sensor — replacement and testing
Warning: Wait for the engine to cool completely before performing this procedure. Warning: Gasoline is extremely flammable, so take extra precautions when you work on any part of the fuel system. The fuel system is under pressure and MUST be relieved before beginning the procedure
Note: The knock sensor is located on the rear of the engine block, directly below the cylinder head.
Replacement
1. Relieve the fuel system pressure (see Fuel and exhaust systems).
2. Disconnect the cable from the negative battery terminal (see Engine electrical systems).
3. Drain the cooling system (see Tune-up and routine maintenance).
4. Remove the intake manifold to access the sensor (see Fuel and exhaust systems).
5. Disconnect the electrical connector. Unscrew the mounting bolt and remove the sensor (see illustration).
i. 5 Knock sensor location
6. Install the knock sensor noting the following specifications:
- Install the sensor in a parallel line to the engine block (connector of sensor should be no more than a 7-degree angle (upward or downward) from a horizontal plane).
- Tighten the sensor mounting bolt to 15 ft-lbs. (20 Nm).
7. Don’t overtighten the sensor or damage may occur. The remainder of installation is the reverse of removal.
Testing
8. Disconnect the knock sensor connector.
9. Using a Digital Volt Ohm Meter (DVOM) set to measure resistance, measure between the two terminals of the knock sensor. With the engine cold (68 degrees-F), resistance should be 120k to 280k ohms.