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 provides an overview of each diagnostic category.

### DTC Descriptors

DTC P0326: Knock Sensor (KS) System Performance Bank 1
DTC P0327: Knock Sensor (KS) Circuit Low Voltage Bank 1
DTC P0328: Knock Sensor (KS) Circuit High Voltage Bank 1
DTC P0331: Knock Sensor (KS) System Performance Bank 2
DTC P0332: Knock Sensor (KS) Circuit Low Voltage Bank 2
DTC P0333: Knock Sensor (KS) Circuit High Voltage Bank 2

### 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.

In order to differentiate between normal engine noise and spark knock, the ECM samples the KS signal. The ECM samples the KS signal for a certain length of time under different engine speeds and loads during non-cylinder knock events. This sampling is used to determine a range of acceptable normal engine noise.

### Conditions for Running the DTC

#### P0326 and P0331

• | Before the ECM can report DTC P0326 or P0331 failed, DTCs P0324, P0335, P0336, and P0338 must run and pass.

• | DTC P0341, P0342, P0343, P0346, P0347, P0348, P0366, P0367, P0368, P0391, P0392, or P0393 is not set.

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

• | The engine speed is greater than 2,200 RPM.

• | DTCs P0326 and P0331 run continuously once the above conditions are met for approximately 20 seconds.

#### P0327, P0328, P0332, and P0333

• | Before the ECM can report DTC P0327, P0328, P0332, or P0333 failed, DTCs P0324, P0335, P0336, and P0338 must run and pass.

• | DTC P0341, P0342, P0343, P0346, P0347, P0348, P0366, P0367, P0368, P0391, P0392, or P0393 is not set.

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

• | The increase in engine speed is less than a range of 500-2300 RPM per second.

• | The increase in engine load is less than a range of 50-100 kPa per second.

• | DTCs P0327, P0328, P0332, and P0332 run continuously once the above conditions are met for approximately 20 seconds.

### Conditions for Setting the DTC

#### P0326 and P0331

The ECM detects a short to ground or a voltage on the KS signal circuits in 25 of 250 test samples. The condition exists for greater than 1 second or for a cumulative of 10 seconds.

#### P0327 or P0332

The ECM detects the KS signal voltage is less than the calculated minimum for a predetermined engine noise level. The condition exists during 2 consecutive tests, for greater 1 second or a cumulative of 10 seconds.

#### P0328 or P0333

The ECM detects the KS signal voltage is greater than the calculated maximum for a predetermined engine noise level. The condition exists during 2 consecutive tests, for greater 1 second or a cumulative of 10 seconds.

### Action Taken When the DTC Sets

DTCs P0326, P0327, P0328, P0331, P0332, and P0333 are Type B DTCs.

### Conditions for Clearing the DTC

DTCs P0326, P0327, P0328, P0331, P0332, and P0333 are Type B DTCs.

### Diagnostic Aids

• | Inspect the KS for physical damage. A KS that is dropped or damaged may cause a DTC to set.

• | Inspect the KS for proper installation. A KS that is loose or over torqued may cause a DTC to set. The KS should be free of thread sealant. The KS mounting surface should be free of burrs, casting flash, and foreign material.

• | The KS must be clear of hoses, brackets, and engine electrical wiring.

• | The normal voltage on the KS signal and low reference circuits is 2.43 volts when the KS is disconnected.

### Reference Information

#### Schematic Reference

Engine Controls Schematics

#### Connector End View Reference

Component Connector End Views

#### Description and Operation

Knock Sensor (KS) System Description

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

#### Scan Tool Reference

Control Module References for scan tool information

### Circuit/System Verification

1. Engine at operating temperature, all accessories OFF. Engine speed greater than 2,000 RPM, observe the appropriate scan tool KS signal voltage parameter. The voltage should be greater than 4 V.
2. Engine idling, move the related harnesses and connectors for the KS circuits while observing the scan tool KS signal voltage parameters. The voltage should remain steady with no abrupt changes.
3. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

### Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the appropriate KS.

Note: If the voltage is not within the specified range on either circuit, test for a wire to wire short, to ground or voltage between the KS circuits.

2. Ignition ON, test for 2-3 V between the signal circuit terminal 1 and ground.

⇒ | If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuits/connections test normal, replace the ECM.

⇒ | If greater than the specified range, test the signal circuit for a short to voltage. If the circuits/connections test normal, replace the ECM.

3. Test for 2-3 V between the low reference circuit terminal 2 and ground.

⇒ | If less than the specified range, test the low reference circuit for a short to ground or an open/high resistance. If the circuits/connections test normal, replace the ECM.

⇒ | If greater than the specified range, test the low reference circuit for a short to voltage. If the circuits/connections test normal, replace the ECM.

4. If all circuits/connections test normal, replace the KS sensor.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Knock Sensor Replacement - Bank 1

• | Knock Sensor Replacement - Bank 2

• | Control Module References for engine control module replacement, setup, and programming