2010 Cadillac CTS Sedan AWD V6-3.6L Page 1330
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) (See: Diagrams/Electrical Diagrams/Powertrain Management/System Diagram)Engine Controls Schematics
(LF1) (See: Diagrams/Electrical Diagrams/Powertrain Management/System Diagram)
Connector End View Reference
Component Connector End Views (See: Diagrams/Connector Views)
Electrical Information Reference
* Circuit Testing (See: Testing and Inspection/Component Tests and General Diagnostics/Circuit Testing/Circuit Testing)
* Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/Connector Repairs/Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (See: Testing and Inspection/Component Tests and General Diagnostics/Circuit
Testing/Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/Wiring Repairs/Wiring Repairs)
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions (See: Diagnostic Trouble Code Descriptions/Powertrain Diagnostic Trouble Code
(DTC) Type Definitions)
Scan Tool Reference
Control Module References (See: Testing and Inspection/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.
瀚慖f 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.
瀚慖f 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.
瀚慖f 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.
瀚慖f 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.
