P06B7
DTC P0324, P0326, P0331, P06B6, or P06B7 (With Heavy Duty L96)
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 (KS) System Performance
DTC P0326
- Knock Sensor (KS) Performance Bank 1
DTC P0331
- Knock Sensor (KS) Performance Bank 2
DTC P06B6
- Control Module Knock Sensor Processor 1 Performance
DTC P06B7
- Control Module Knock Sensor Processor 2 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 frequency of the knock sensor signal. The ECM receives the knock sensor signal through 2 isolated signal circuits for each bank. The ECM learns a minimum knock sensor noise level for all of the engine speed ranges. The ECM monitors for a normal knock sensor signal. The ECM monitors the internal knock sensor processor by verifying a 20 KHz signal generated on the output circuit is detected on the return circuit.
Conditions for Running the DTC
P0324, P0326 and P0331-Excessive Knock Detection Mode
* Engine speed is between 1,500-8,500 RPM.
* Engine is running at least 1 S.
* The engine coolant temperature (ECT) is warmer than -40°C (-40°F).
* The intake air temperature (IAT) is warmer than -40°C (-40°F).
* The DTCs run continuously when the above conditions are met.
P0324, P0326 and P0331-Abnormal Noise Detection Mode-Improperly Bolted Knock Sensor
* Engine speed is between 2,500-8,500 RPM.
* Engine is running at least 1 S.
* The ECT is warmer than -40°C (-40°F).
* The IAT is warmer than -40°C (-40°F).
* The DTCs run continuously when the above conditions are met.
P06B6 and P06B7
* Engine speed is between 400-3,500 RPM.
* Engine is running at least 4 S.
* The DTCs run continuously when the above conditions are met.
Conditions for Setting the DTC
P0324
The ECM detects that the knock sensor signal indicates an excessive engine knock or noise is present in at least a single cylinder.
P0326 and P0331
* The ECM detects that the knock sensor signal indicates the sensor harness is connected, but the sensor is not properly bolted to the engine.
OR
* The ECM detects that the knock sensor signal indicates an excessive engine knock is present in an entire bank.
P06B6 and P06B7
The ECM has detected an internal knock sensor processor fault.
Action Taken When the DTC Sets
* DTCs P0324, P0326, P0331, P06B6, and P06B7 are Type B codes.
* The ignition timing is retarded to reduce the potential of engine damaging spark knock.
Conditions for Clearing the DTC
DTCs P0324, P0326, P0331, P06B6, and P06B7 are Type B codes.
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 mounting surface should be free of burrs, casting flash, and foreign material.
* The KS must be clear of hoses, brackets, and engine electrical wiring.
Reference Information
Schematic Reference
Engine Controls Schematics (except L96) [1][2]Electrical DiagramsEngine Controls Schematics (L96) [1][2]Electrical Diagrams
Connector End View Reference
Component Connector End Views 1-2 Shift Solenoid (SS) Valve (M30)
Description and Operation
Electronic Ignition System Description Description and Operation
Electrical Information Reference
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Circuit Testing Circuit Testing
* Wiring Repairs Wiring Repairs
* Connector Repairs Connector 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
Special Tools
J 35616 GM Approved Terminal Test Kit
Circuit/System Verification
1. Engine idling, observe the DTC information with a scan tool. Verify DTC P0325, P0327, P0328, P0330, P0332, P0333, P06B6, and P06B7 is not set.
• If a DTC is set with P06B6 or P06B7, refer to Diagnostic Trouble Code (DTC) List - Vehicle Diagnostic Trouble Code (DTC) List - Vehicle for further diagnosis.
2. DTCs P06B6 and P06B7 indicate an internal K20 ECM circuitry failure. Verify the external knock sensor circuits and connectors for proper condition.
• If DTC P06B6 or P06B7 is set, and no external knock sensor circuit issues exist; replace the K20 ECM.
3. Ignition OFF, inspect for the following:
* Inspect the applicable B68 KS for physical damage. A B68 KS that is dropped or damaged may cause a DTC to set
* Inspect the B68 KS for proper installation. A B68 KS that is loose or over torqued may cause a DTC to set. The B68 KS should be free of thread sealant. The B68 KS mounting surface should be free of burrs, casting flash, and foreign material
* The B68 KS 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 Symptoms - Engine Mechanical
• If a condition is found, repair as necessary.
4. If there is no mechanical condition, test or replace the B68 KS sensor.
5. 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 Verification Tests after completing the diagnostic procedure.
* Knock Sensor 1 Replacement Knock Sensor 1 Replacement
* Knock Sensor 2 Replacement Knock Sensor 2 Replacement
* Control Module References Control Module References for ECM replacement, programming, and setup.