P0325
DTC P0324-P0328, or P06B6 (LUW)
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 P0324
- Knock Sensor System Performance
DTC P0325
- Knock Sensor Circuit
DTC P0326
- Knock Sensor Performance
DTC P0327
- Knock Sensor Circuit Low Voltage
DTC P0328
- Knock Sensor Circuit High Voltage
DTC P06B6
- Control Module Knock Sensor Processor 1 Performance
Diagnostic Fault Information
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 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 2 isolated signal circuits. The ECM learns a minimum knock sensor noise level for all of the RPM range. The ECM monitors for a normal knock sensor signal. The ECM generates a 20 KHz signal on the output circuit and monitors that it is sent back and detected on the return circuit. The ECM processes the return signal to verify the internal knock sensor processor.
Conditions for Running the DTC
P0325, P0327, and P0328
* Engine speed is between 400-8 500 RPM.
* The engine coolant temperature (ECT) is greater than -40°C (-40°F).
* The intake air temperature (IAT) is greater than -40°C (-40°F).
* The DTCs run continuously when the above conditions are met.
P0324, and P0326 Excessive Knock Detection Mode
* Engine speed is between 580-8 500 RPM.
* The ECT is greater than -40°C (-40°F).
* The IAT is greater than -40°C (-40°F).
* The DTCs run continuously when the above conditions are met.
P0324 and P0326 Abnormal Noise Detection Mode, Improperly Bolted Knock Sensor
* Engine speed is between 2 200-8 500 RPM.
* The ECT is greater than -40°C (-40°F).
* The IAT is greater than -40°C (-40°F).
* The DTCs run continuously when the above conditions are met.
P06B6
* Engine speed is between 400-4 000 RPM.
* The ECT is greater than -40°C (-40°F).
* The IAT is greater than -40°C (-40°F).
* The DTC runs continuously when the above conditions are met.
Conditions for Setting the DTC
P0324
The knock sensor signal indicates an excessive engine knock is present for greater than 10 s for at least 1 single cylinder.
P0325
The knock sensor signal circuits are open for greater than 5 s.
P0326
* The signal indicates the sensor harness is connected, but the sensor is not properly bolted to the engine.
* The above condition exist for greater than 10 s.
or
* The knock sensor signal indicates an excessive engine knock is present.
* The above condition exist for greater than 10 s.
P0327
The knock sensor signal circuits are shorted to ground for greater than 5 s.
P0328
The knock sensor signal circuits are shorted to voltage for greater than 5 s.
P06B6
The ECM has detected an internal knock sensor processor fault.
Action Taken When the DTC Sets
* DTCs P0324, P0325, P0326, P0327, P0328, and P06B6 are Type B DTCs.
* The ignition timing is retarded to reduce the potential of engine damaging spark knock.
Conditions for Clearing the DTC
DTCs P0324, P0325, P0326, P0327, P0328, and P06B6 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.
Reference Information
Schematic Reference
Engine Controls Schematics (LUW) [1][2]Electrical Diagrams
Connector End View Reference
Component Connector End Views Sunshade - Left (D6I)
Description and Operation
Electronic Ignition System Description Description and Operation
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 Control Module References for scan tool information
Circuit/System Verification
1. Engine at operating temperature, all accessories OFF, and engine speed greater than 2 000 RPM, observe the Knock Retard and Total Knock Retard parameters. The parameters should be 0°.
2. Engine idling, move the related harnesses and connectors for the knock sensor circuits while observing the scan tool Knock Retard and Total Knock Retard parameters. The parameters 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
P0324 and P0326
1. Ignition OFF, Disconnect the B68 Knock Sensor harness connector.
2. Connect the DMM between the B68 Knock Sensor signal circuit terminal 1 and the B68 Knock Sensor low reference circuit terminal 2 on the sensor side of the B68 Knock Sensor harness connector.
3. Set the DMM to the 400 mV AC hertz scale and wait for the DMM to stabilize at 0 Hz.
Note: DO NOT tap on plastic engine components.
4. Tap on the engine block with a non-metallic object near the B68 Knock Sensor while observing the signal indicated on the DMM.
5. The DMM should display a fluctuating frequency while tapping on the engine block.
• If the DMM does not display a fluctuating frequency while tapping on the engine block, replace the B68 Knock Sensor harness connector.
6. Ignition ON, engine OFF.
7. Ignition ON, test for 1-4 V between each of the following circuits and ground on the K20 Engine Control Module side of the harness connector:
* The B68 Knock Sensor signal circuit, terminal 1
* The B68 Knock Sensor signal circuit, terminal 2
• If less than the specified range, test the circuits for a short to ground or an open/high resistance. If the circuits test normal, replace the K20 Engine Control Module.
• If greater than the specified range, test the circuits for a short to voltage. If the circuits test normal, replace the K20 Engine Control Module.
8. If the circuits test normal, replace the B68 Knock Sensor.
P06B6
* Verify that the following DTCs are not set: DTC P0325, P0327, and P0328.
• If any of the DTCs are set, diagnose them first.
* DTC P06B6 indicates an internal ECM circuitry failure. Replace the K20 Engine Control Module if no external knock sensor circuit issues exist.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.
* Knock Sensor Replacement (LDE, LXV, LUW, 2H0 and LFH) Service and Repair
* Control Module References Control Module References for ECM replacement, programming, and setup