P0327

DTC P0326, P0327, P0328, P0331, P0332, or P0333 (w/LLT)

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions) provides an overview of each diagnostic category.

DTC Descriptors
DTC P0326
- Knock Sensor Performance Bank 1

DTC P0327
- Knock Sensor Circuit Low Voltage Bank 1

DTC P0328
- Knock Sensor Circuit High Voltage Bank 1

DTC P0331
- Knock Sensor Performance Bank 2

DTC P0332
- Knock Sensor Circuit Low Voltage Bank 2

DTC P0333
- Knock Sensor Circuit High Voltage Bank 2

Circuit/System Description

The knock sensor is a piezoelectric device that produces an AC voltage of different amplitude and frequency depending on the level of engine mechanical vibration. The knock sensor system monitors the knock sensor in order to determine if detonation or spark knock is present. If the knock sensor system determines that excessive knock is present, the engine control module (ECM) retards the spark timing based on the signal from the knock sensor system. The knock sensor 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 knock sensor signal. The ECM samples the knock sensor 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
* DTC P0324 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.
* The increase in engine speed is less than 500-2,300 RPM per second.
* The increase in engine load is less than a range of 50-100 kPa per second.
* DTCs P0326 and P0331 run continuously once the above conditions are met for approximately 20 s.

P0327, P0328, P0332, and P0333
* DTC P0324 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 s.

Conditions for Setting the DTC

P0326 and P0331

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

P0327 or P0332

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

P0328 or P0333

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

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 knock sensor for physical damage. 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.
* The knock sensor must be clear of hoses, brackets, and engine electrical wiring.
* The normal voltage on the knock sensor signal and low reference circuits is 2.43 V when the knock sensor is disconnected.

Reference Information
Schematic Reference

Engine Controls Schematics (LLT) ([1][2]Electrical Diagrams)Engine Controls Schematics (LF1) ([1][2]Electrical Diagrams)
Connector End View Reference

Component Connector End Views (Connector Views)
Electrical Information Reference

* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing For Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions (Powertrain Diagnostic Trouble Code (DTC) Type Definitions)
Scan Tool Reference

Control Module References (Programming and Relearning) 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 knock sensor signal voltage parameter. The voltage should be greater than 4 V.
2. Engine idling, move the related harnesses and connectors for the knock sensor circuits while observing the scan tool knock sensor 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 B68 knock sensor.

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 knock sensor circuits.

2. Ignition ON, test for 2-3 V between the signal circuit terminal A 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 K20 ECM.
• If greater than the specified range, test the signal circuit for a short to voltage. If the circuits/connections test normal, replace the K20 ECM.

3. Test for 2-3 V between the low reference circuit terminal B 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 K20 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 K20 ECM.

4. If all circuits/connections test normal, replace the B68 knock sensor sensor.

Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* Knock Sensor Replacement - Bank 1 (Knock Sensor Replacement - Bank 1)
* Knock Sensor Replacement - Bank 2 (Knock Sensor Replacement - Bank 2)
* Control Module References (Programming and Relearning) for ECM replacement, setup, and programming