Diagnostic Aids

Perform this test only when directed by QUICK TEST. This test is intended to diagnose the following:

Knock Sensor (KS)
Wiring Harness Circuits: (KS & SIG RTN)
Powertrain Control Module (PCM)

To prevent replacement of good components, be aware the following non-EEC related areas may be at fault:

Poor Fuel Quality
Ignition System
Ignition Or Valve Timing
Engine Mechanical Condition

1) KOER & Continuous Memory DTCs P0325, P0326 (KS1), Or P0330 & P0331 (KS2): Check Knock Sensor Voltage

DTCs P0325, P0326, P0330 and P0331 indicate spark knock voltage fell below minimum calibrated limit or exceeded maximum calibrated limit. DTC P0325 and P0326 are for knock sensor No. 1 (cylinder bank that includes cylinder No. 1). DTCs P0330 and P0331 are for knock sensor No. 2. Possible causes for these faults are:
- Open In KS Circuit
- KS Circuit Shorted To PWR Or GND
- Faulty Knock Sensor
- Faulty Powertrain Control Module (PCM)
Turn ignition switch to OFF position. Ensure knock sensor is connected. Perform DRIVE CYCLE PROCEDURES under ADDITIONAL SYSTEM FUNCTIONS. Ensure COMPREHENSIVE COMPONENT MONITOR (CCM) MONITOR (TRANSMISSION) PROCEDURE is performed. Connect scan tool to Data Link Connector (DLC). Turn ignition switch to ON position. Using scan tool, select KS PID from PID/DATA MONITOR & RECORD menu. If PID voltage is less than .5 volt, go to next step. If PID voltage is .5 volt or more, go to step 6).

2) Check Knock Sensor Circuit Resistance

Turn ignition switch to OFF position. Disconnect PCM connector(s). Using a DVOM, measure resistance between specified PCM harness connector KS (+) and KS (-) terminals. See KNOCK SENSOR CIRCUIT PCM TERMINAL IDENTIFICATION table. If resistance is 4.39-5.35 megohms, go to step 7). If resistance is more than 5.35 megohms, go to next step. If resistance is less than 4.39 megohms, go to step 5).

KNOCK SENSOR CIRCUIT PCM TERMINAL IDENTIFICATION

Application	PCM KS (-) Terminal No.	PCM KS (+) Terminal No.
All Models	32	57

3) Check Knock Sensor Resistance

Turn ignition switch to OFF position. Disconnect KS connector. Using a DVOM, measure resistance between both KS connector terminals. If resistance is 4.39-5.35 megohms, go to next step. If resistance is not 4.39-5.35 megohms, replace KS.

4) Check For Open Circuit

Ensure PCM connector(s) is disconnected. Using a DVOM, measure resistance of KS (+) and KS (-) circuits between PCM harness connector and knock sensor harness connector. See KNOCK SENSOR CIRCUIT PCM TERMINAL IDENTIFICATION table. If both resistance measurements are less than 5 ohms, go to step 7). If either resistance measurement is 5 ohms or more, repair open in affected circuit.

5) Check For Short Between KS (+) & KS (-) Circuits

Disconnect KS connector. Using a DVOM, measure resistance between specified PCM harness connector KS (+) and KS (-) terminals. See KNOCK SENSOR CIRCUIT PCM TERMINAL IDENTIFICATION table. If resistance is more than 10 k/ohms, go to step 7). If resistance is 10 k/ohms or less, repair short between circuits.

6) Check KS Circuits For Short To Power

Turn ignition switch to OFF position. Disconnect PCM connector(s). Turn ignition switch to ON position. Using a DVOM, measure voltage between specified PCM harness connector KS (+) and KS (-) terminals and battery negative terminal. See KNOCK SENSOR CIRCUIT PCM TERMINAL IDENTIFICATION table. If voltage is less than .5 volt, replace PCM. If voltage is .5 volt or more, repair short to VPWR in affected circuit.

7) Check KS Circuits For Short To Ground

Ensure ignition switch is turned to OFF position. Connect PCM harness connector(s). Using a DVOM, measure resistance between KS harness connector KS (+) and KS (-) terminals and battery negative terminal. See KNOCK SENSOR CIRCUIT PCM TERMINAL IDENTIFICATION table. If resistance is 10 k/ohms or less, go to next step. If resistance is more than 10 k/ohms, replace knock sensor. Reconnect all components and repeat QUICK TEST . If fault is still present, go to next step.

8) Check PCM For Short To Ground

Ensure ignition switch is turned to OFF position. Disconnect PCM harness connector(s). Using a DVOM, measure resistance between KS harness connector KS (+) and KS (-) terminals. If resistance is 10 k/ohms or less, repair short to ground in affected circuit. If resistance is more than 10 k/ohms, replace PCM. Reconnect all components and repeat QUICK TEST .