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DTC P0327 (LLU)

DTC P0327 (LLU)

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 Descriptor

DTC P0327 00

Knock Sensor Circuit Low Voltage

Diagnostic Fault Information

Circuit Short to Ground Open/High Resistance Short to Voltage Signal Performance
Signal Circuit

P0327 00

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Low Reference

P0327 00

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Circuit/System Description

The knock sensor system 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 alternating current (AC) signal that varies with the level of vibration when the engine is running. The ECM adjusts the spark timing according to the amplitude and frequency of the knock sensor signal. The ECM receives a knock sensor signal via a signal circuit and a low reference circuit. The ECM programmes the lowest noise level for the knock sensor at idle and uses calibrated values for the remaining engine speed range. The ECM should monitor whether a normal knock sensor signal lies within the noise level.

Conditions for Running the DTC


• The engine speed is greater than 2 000 RPM.

• Engine coolant temperature (ECT) is greater than 39°C (102°F).

• DTC P0327 00 runs continuously once the above condition is met.


Conditions for Setting the DTC

The ECM detects the knock sensor signal circuit is shorted to ground open, or shorted to power.

Action Taken When the DTC Sets


• DTC P0327 00 is a Type C DTC.

• The service vehicle soon indicator will illuminate.


Conditions for Clearing the DTC

DTC P0327 00 is a Type C DTC.

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 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. With the engine running, check the DTC Information with the scan tool. DTC P0327 00 should not be set.

2. 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 B68 Knock Sensor.

2. Ignition ON, test for less than 0.3 V between the low reference circuit terminal 2 and ground.

3. If greater than the specified range, test the low reference circuit for a short to voltage. If the circuit tests normal, replace the K20 Engine Control Module.

4. Ignition ON, test for less than 0.3 V between the signal circuit terminal 1 and ground.

5. If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the K20 Engine Control Module.

6. Ignition OFF, disconnect the ECM X1 harness connector at the K20 Engine Control Module.

7. Test for less than 5 Ω on all B68 Knock Sensor harness connector sensor circuits between the following terminals:

• The low reference circuit terminal 2 to the corresponding ECM terminal X1-36

• The signal circuit terminal 1 to the corresponding ECM terminal X1-51

• If greater than 5 Ω, repair the affected circuit.

8. If all circuits test normal, test or replace the B68 Knock Sensor.


Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.


• Knock Sensor Replacement

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