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 00: Knock Sensor Performance
DTC P06B6 00: Internal Control Module Knock Sensor Processor Performance

### Circuit/System Description

The knock sensor enables the engine control module (ECM) to control the ignition timing for the best possible performance while protecting the engine from potentially damaging levels of detonation. The knock sensor produces an AC voltage signal that varies depending on the vibration level during engine operation. The ECM adjusts the spark timing based on the amplitude and the frequency of the knock sensor signal. The ECM receives the knock sensor signal through a signal circuit. The ECM supplies a ground circuit to the knock sensor through a low reference circuit. The ECM also supplies a shielded ground circuit to the knock sensor. The ECM learns a knock sensor noise level at idle and uses calibrated values for the rest of the engine speed range. The ECM should monitor a normal knock sensor signal within the noise channel.

### Conditions for Running the DTC

• | The engine speed is greater than 700 RPM.

• | The engine speed is between 700 to 2500 RPM for DTC P06B6 00.

• | The airflow into the engine is between 40 to 2000 mg/cylinder

• | This DTC runs continuously within the enabling conditions.

• | DTCs P0326 00, and P06B6 00 run continuously once the above conditions are met.

### Conditions for Setting the DTC

#### P0326 00

The control module detects an overactive knock sensor.

#### P06B6 00

The control module detects an internal circuitry fault.

### Action Taken When the DTC Sets

DTCs P0326 00, and P06B6 00 are Type C DTCs.

### Conditions for Clearing the DTC

DTCs P0326 00, and P06B6 00 are Type C DTCs.

### Diagnostic Aids

• | Inspect the knock sensor for physical damage and proper installation. A knock sensor that is dropped or damaged may cause a DTC to set.

• | Inspect the knock sensor for proper installation. A knock sensor that is loose or over torqued may cause a DTC to set. The knock sensor should be free of thread sealant.

• | The knock sensor mounting surface should be free of burrs, casting flash, and foreign material.

### 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

#### Special Tools

For equivalent regional tools, refer to Special Tools.

### Circuit/System Testing

1. Engine idling, observe the DTC information with a scan tool. Verify DTC P06B6 00 is not set.

⇒ | If the DTC is set, replace the K20 Engine Control Module (ECM).

2. Ignition OFF, inspect for the following:

• | Inspect the B68 Knock Sensor for physical damage. A B68 Knock Sensor that is dropped or damaged may cause a DTC to set

• | Inspect the B68 Knock Sensor for proper installation. A B68 Knock Sensor that is loose or over torqued may cause a DTC to set. The B68 Knock Sensor should be free of thread sealant. The B68A Knock Sensor mounting surface should be free of burrs, casting flash, and foreign material

• | The B68A Knock Sensor must be clear of hoses, brackets, and engine electrical wiring

• | Inspect for loose accessory brackets

• | Inspect for serpentine belt and tensioner wear

• | Inspect for an engine mechanical condition--Refer to Symptoms - Engine Mechanical

⇒ | If a condition is found, repair as necessary.

3. If there is no mechanical condition, test or replace the B68 Knock Sensor.
4. 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.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Knock Sensor Replacement

• | Control Module References for ECM replacement, setup, and programming