Buick Regal: DTC P0325, P0327, P0328, P0330, P0332, or P0333
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 Descriptors
DTC P0325
Knock Sensor 1 Circuit
DTC P0327
Knock Sensor 1 Circuit Low Voltage
DTC P0328
Knock Sensor 1 Circuit High Voltage
DTC P0330
Knock Sensor 2 Circuit
DTC P0332
Knock Sensor 2 Circuit Low Voltage
DTC P0333
Knock Sensor 2 Circuit High Voltage
Diagnostic Fault Information
Circuit/System Description
The knock sensors enable 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 sensors produce an alternating current (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 two knock sensor signals. The ECM receives each knock sensor
signal through a
dedicated circuit. The ECM learns a minimum knock sensor noise level for all of
the engine speed
ranges and monitors the normal knock sensor signal. The ECM monitors the
internal knock sensor
processor test circuits which perform the open circuit diagnostic.
Conditions for Running the DTCs
P0325 and P0330
- Engine is running for 2 s or greater.
- Engine speed is between 400 - 5, 500 RPM for 75 or more cumulative
revolutions.
- Engine air flow is between 20 - 2000 mg per cylinder.
- The engine coolant temperature (ECT) is -40ºC (-40ºF) or warmer.
- The intake air temperature (IAT) sensor 1 is -40ºC (-40ºF) or warmer.
P0327, P0328, P0332, and P0333
Engine speed is less than 8, 500 RPM.
The DTCs run continuously when the above conditions are met.
Conditions for Setting the DTCs
P0325
The ECM detects knock sensor 1 signal circuit is open.
P0327
The ECM detects knock sensor 1 signal circuit is shorted to ground.
P0328
The ECM detects knock sensor 1 signal circuit is shorted to voltage.
P0330
The ECM detects knock sensor 2 signal circuit is open.
P0332
The ECM detects knock sensor 2 signal circuit is shorted to ground.
P0333
The ECM detects knock sensor 2 signal circuit is shorted to voltage.
Action Taken When the DTCs Set
- DTCs P0325, P0327, P0328, P0330, P0332, and P0333 are Type B DTCs.
- The ignition timing is retarded to reduce the potential of engine
damaging spark knock.
Conditions for Clearing the DTCs
DTCs P0325, P0327, P0328, P0330, P0332, and P0333 are Type B DTCs.
Diagnostic Aids
The following conditions listed below may cause a knock sensor DTC to set:
- Sensor damage.
- Knock sensor and engine mounting surface burrs, casting flash, and
foreign material.
- Close proximity of hoses, brackets, and engine wiring.
- Loose brackets.
- Loose or broken accessory drive belts, brackets, components.
- An engine mechanical condition. Refer to Symptoms - Engine Mechanical.
Reference Information
Schematic Reference
Engine Controls Wiring Schematics (LTG)
Connector End View Reference
Component Connector End View Index
Description and Operation
Electronic Ignition 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. Engine Running.
2. Verify DTC P0325, P0327, P0328, P0330, P0332, or P0333, is not set.
Refer to Circuit/System Testing.
- Go to next step: If the DTC is not set
3. Verify the appropriate B68 Knock Sensor mounting bolt is properly
tightened. Refer to Fastener Specifications.
- If not tightened to the correct specification
Repair a necessary.
- Go to next step: If tightened to the correct specification
4. Verify the scan tool parameters listed below display No while moving the
related harnesses and
connectors of the B68 Knock Sensor.
- Cylinder 1 Knock Detected
- Cylinder 2 Knock Detected
- Cylinder 3 Knock Detected
- Cylinder 4 Knock Detected
- If No is not displayed
Repair the wiring harness or connectors.
- Go to next step: If No is displayed
5. Operate the vehicle within the conditions for running the DTC. You may
also operate the vehicle
within the conditions that you observed from the Freeze Frame/Failure Records
data.
6. Verify the DTC does not set.
Refer to Circuit/System Testing.
- Go to next step: If the DTC does not set
7. All OK.
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the appropriate B68
Knock Sensor, ignition ON.
2. Test for 1 - 2 V between the low signal circuit terminal 2 or B and ground.
- Ignition OFF, disconnect the harness connector at the K20 Engine Control
Module.
- Test for infinite resistance between the low signal circuit terminal 2
or B and ground.
- If less than infinite resistance, repair the short to ground on the
circuit.
- Go to next step: If infinite resistance.
- Test for less than 2 Ω in the low signal circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the K20 Engine Control Module.
- Ignition OFF, disconnect the harness connector at the K20 Engine Control
Module, ignition
ON.
- Test for less than 1 V between the low signal circuit and ground.
- If 1 V or greater, repair the short to voltage on the circuit.
- If less than 1 V, replace the K20 Engine Control Module.
- Go to next step: If between 1 - 2 V
3. Test for 2 - 4 V between the high signal circuit terminal 1 or A and
ground.
- Ignition OFF, disconnect the harness connector at the K20 Engine Control
Module.
- Test for infinite resistance between the high signal circuit terminal 1
or A and ground.
- If less than infinite resistance, repair the short to ground on the
circuit.
- Go to next step: If infinite resistance.
- Test for less than 2 Ω in the high signal circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the K20 Engine Control Module.
- Ignition OFF, disconnect the harness connector at the K20 Engine Control
Module, ignition
ON.
- Test for less than 1 V between the high signal circuit and ground.
- If 1 V or greater, repair the short to voltage on the circuit.
- If less than 1 V, replace the K20 Engine Control Module.
- Go to next step: If between 2 - 4 V
4. Test or replace the B68 Knock Sensor.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the repair.
- Knock Sensor Replacement (Position 2) or Knock Sensor Replacement
(Position 1)
- Control Module References for engine control module replacement,
programming, and setup.
READ NEXT:
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.
Diag
Diagnostic Instructions
Perform the Diagnostic System Check prior to using this diagnostic
procedure: Diagnostic
System Check - Vehicle
Review the description of Strategy Based Diagnosis: Strate
Diagnostic Instructions
Perform the Diagnostic System Check prior to using this diagnostic
procedure: Diagnostic
System Check - Vehicle
Review the description of Strategy Based Diagnosis: Strate
SEE MORE:
* PLEASE READ THIS FIRST *
NOTE: Examples used in this article are general in nature and do not
necessarily
relate to a specific engine or system. Illustrations and procedures have
been chosen to guide mechanic through engine overhaul process.
Descriptions of processes of cleaning, inspection, ass
To ensure proper engine
performance and long life, careful
attention must be paid to engine oil.
Following these simple, but
important steps will help protect
your investment:
Use engine oil approved to the
proper specification and of the
proper viscosity grade. See
"Selecting the Right Engine