DTC P0325 or P0326
DTC P0325 or P0326
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 P0325 00
- Knock Sensor Circuit
DTC P0326 00
- Knock Sensor 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 A/C 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 and a low reference circuit. The ECM learns a minimum knock sensor noise level at idle and uses calibrated values for the rest of the RPM range. The ECM should monitor a normal knock sensor signal within the noise channel.
Conditions for Running the DTC
* The engine is running.
* The engine speed is greater than 2500 RPM.
* DTC P0340 00, P0341 00, P0365 00, P0366 00, P0335 00, P0336 00, P0601 00, P0602 00 or P0604 00 are not set.
* This DTC runs continuously within the enabling conditions.
Conditions for Setting the DTC
The knock signal is checked continuously by a range check of the signal and with two algorithms, which observe the signal bandwidth.
Action Taken When the DTC Sets
DTCs P0325 00, P0326 00 are Type B DTCs.
Conditions for Clearing the DTC
DTCs P0325 00, P0326 00 are Type B 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.
* Loosen the mounting screw of the knock sensor and tighten the screw again using the specified torque. A knock sensor that is loose or over torqued may cause a DTC to set.
* Search the engine block and its environment for parts that vibrate but are not supposed to. Loose or faulty parts may cause high-frequency vibrations in the engine block which can disturb the knock sensor.
Reference Information
Schematic Reference
Engine Controls Schematics ([1][2]Electrical Diagrams)
Connector End View Reference
Component Connector End Views (Connector End Views By Name)
Description and Operation
Knock Sensor 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 (Programming and Relearning)for scan tool information
Circuit/System Testing
1. Ignition OFF.
2. Disconnect the K20 Engine Control Module harness connector X2 and B68 Knock Sensor.
3. Ignition ON, test for less than 0.3 V between the K20 Engine Control Module harness connector X2 terminal 14 and ground.
• If greater than the specified range, test the circuit for a short to voltage.
4. Test for less than 0.3 V between the K20 Engine Control Module harness connector X2 terminal 36 and ground.
• If greater than the specified range, test the circuit for a short to voltage.
5. Ignition OFF, test for greater than 500 kohm between the K20 Engine Control Module harness connector X2 terminal 14 and ground.
• If less than the specified range, test the circuit for a short to ground.
6. Test for greater than 500 kohm between the K20 Engine Control Module harness connector X2 terminal 36 and ground.
• If less than the specified range, test the circuit for a short to ground.
7. If the circuits test normal, replace the B68 Knock Sensor.
8. Verify the DTC does not reset.
• If the DTC resets, replace the K20 Engine Control Module.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Knock Sensor Replacement (LDE, LXV, 2H0 and LUW) (Service and Repair)
* Symptoms - Engine Controls (Symptoms - Engine Controls)
* Symptoms - Engine Mechanical (Symptoms - Engine Mechanical)
* Control Module References (Programming and Relearning)for ECM replacement, setup, and programming