For 1990-2009 cars

### Diagnostic Instructions

• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

• | Review Strategy Based Diagnosis for an overview of the diagnostic approach.

• | Diagnostic Procedure Instructions provide an overview of each diagnostic category.

### DTC Descriptor

DTC P0324: Knock Sensor (KS) Module Performance

### Circuit/System Description

The knock sensor (KS) is a piezoelectric device that produces an AC voltage of different amplitude and frequency depending on the level of engine mechanical vibration. The KS system monitors the knock sensor in order to determine if detonation or spark knock is present. If the KS system determines that excessive knock is present, the engine control module (ECM) retards the spark timing based on the signal from the KS system. The KS produces an AC signal when specific frequencies are detected. The ECM then retards the timing until knock is controlled.

The ECM tests the functionality of the internal knock sensor signal evaluation circuitry. The KS circuitry within the ECM is responsible for receiving, amplifying, filtering, and evaluating the AC voltage and frequency from the knock sensors. The ECM performs two tests that determine if the internal circuitry within the ECM is functioning correctly.

#### Test One

The ECM internally turns OFF the knock sensor signal circuits. The ECM then applies different test signals to the internal KS circuitry to verify that each test signal output response is within range. If the ECM detects that any of the test signals are not within range, this DTC sets.

#### Test Two

The ECM internally turns OFF the knock sensor signal circuits. The ECM then tests for any output response when no test signals are applied. If the ECM detects an output response, this DTC sets.

#### Test Three

The ECM internally turns OFF the knock sensor signal circuits. The ECM generates an internal test pulse and monitors the return signal. If the return test pulse is less than a calibrated threshold, this DTC sets.

### Conditions for Running the DTC

• | The ECM is controlling spark.

• | The engine coolant temperature is warmer than 60°C (140°F).

• | DTC P0324 runs continuously once the above conditions are met.

### Conditions for Setting the DTC

• | The ECM detects an incorrect response to the self tests performed on the internal KS circuitry.

• | The condition exists for greater than 4 seconds or for a cumulative of 50 seconds.

### Action Taken When the DTC Sets

DTC P0324 is a Type B DTC.

### Conditions for Clearing the DTC

DTC P0324 is a Type B DTC.

### Reference Information

#### Description and Operation

Knock Sensor (KS) System Description

#### DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

#### Scan Tool Reference

Control Module References for scan tool information

### Circuit/System Verification

Important: If you can hear an engine knock, repair the engine mechanical condition before proceeding with this diagnostic. Refer to Symptoms - Engine Mechanical.

1. Observe and record the Freeze Frame/Failure Records for DTC P0324.

⇒ | If DTC P0335, P0336, or P0338 also set, refer to DTC P0335, P0336, or P0338.

2. Clear the DTCs with a scan tool.
3. Turn OFF the ignition for 30 seconds.
4. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure records. DTC P0324 should not set.

⇒ | If DTC P0324 failed this ignition, replace the engine control module (ECM).

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for ECM replacement, setup, and programming