DTC P0326, P0327, P0328, P0331, P0332, or P0333 (LAU)
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DTC P0326, P0327, P0328, P0331, P0332, or P0333 (LAU)
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DTC P0326
Knock Sensor System Performance Bank 1
DTC P0327
Knock Sensor Circuit Low Voltage Bank 1
DTC P0328
Knock Sensor Circuit High Voltage Bank 1
DTC P0331
Knock Sensor System Performance Bank 2
DTC P0332
Knock Sensor Circuit Low Voltage Bank 2
DTC P0333
Knock Sensor Circuit High Voltage Bank 2
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Circuit/System Description
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The knock sensor is a piezoelectric device that produces an AC voltage of different amplitude and frequency depending on the level of engine mechanical vibration. The knock sensor system monitors the knock sensor in order to determine if detonation or spark knock is present. If the knock sensor system determines that excessive knock is present, the engine control module (ECM) retards the spark timing based on the signal from the knock sensor system. The knock sensor produces an AC signal when specific frequencies are detected. The ECM then retards the timing until knock is controlled.
In order to differentiate between normal engine noise and spark knock, the ECM samples the knock sensor signal. The ECM samples the knock sensor signal for a certain length of time under different engine speeds and loads during non-cylinder knock events. This sampling is used to determine a range of acceptable normal engine noise.
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Conditions for Running the DTC
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P0326 and P0331
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The engine speed is greater than 1,600 RPM.
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The ECM is controlling spark.
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DTCs P0326 and P0331 run continuously once the above conditions are met.
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P0327, P0328, P0332, and P0333
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DTCs P0324, P0335, P0336, P0338, P0341, P0342, P0343, P0346, P0347, P0348, P0366, P0367, P0368, P0391, P0392, P0393 are not set.
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The engine speed is greater than 1,960 RPM.
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The ECM is controlling spark.
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The increase in engine speed is less than a range of 1,400-3,700 RPM per second.
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The engine load is in the range of 35-65 kPa per second.
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DTCs P0327, P0328, P0332, and P0332 run continuously once the above conditions are met for approximately 20 s.
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Conditions for Setting the DTC
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P0326 and P0331
The ECM detects a knock sensor signal voltage that is not in the range of a predetermined engine noise level in 25 of 250 test samples. The condition exists for greater than 1 s or for a cumulative of 10 s.
P0327 or P0332
The ECM detects a knock sensor signal voltage that is less than the predetermined minimum engine noise level for greater than 1 s or for a cumulative of 10 s.
P0328 or P0333
The ECM detects the knock sensor signal voltage is greater than predetermined maximum engine noise level for greater than 1 s or for a cumulative of 10 s.
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Action Taken When the DTC Sets
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DTCs P0326, P0327, P0328, P0331, P0332, and P0333 are Type B DTCs.
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Conditions for Clearing the DTC
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DTCs P0326, P0327, P0328, P0331, P0332, and P0333 are Type B DTCs.
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Inspect the knock sensor for physical damage. A knock sensor that is dropped or damaged may cause a DTC to set.
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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.
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The knock sensor must be clear of hoses, brackets, and engine electrical wiring.
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With the knock sensor disconnected, the normal voltage measured from the knock sensor signal or the low reference circuit to ground is between 2.30-2.80 V.
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Schematic Reference
Engine Controls Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Knock Sensor System Description
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References
for scan tool information
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Circuit/System Verification
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1.
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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 4.0 V.
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2.
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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.
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3.
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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.
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1.
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Ignition OFF, disconnect the harness connector at the appropriate B68 knock sensor.
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2.
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Note
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If the voltage is not within the specified range on either circuit, test for a wire to wire short, short to ground, or short to voltage between the knock sensor circuits.
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Ignition ON, test for 2-3 V between the signal circuit terminal A or 1 and ground.
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3.
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If 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.
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4.
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If greater than the specified range, test the signal circuit for a short to voltage. If the circuits/connections test normal, replace the K20 ECM.
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5.
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Test for 2-3 V between the low reference circuit terminal B or 2 and ground.
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6.
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If 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.
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7.
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If 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.
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8.
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If all circuits/connections test normal, test or replace the appropriate B68 knock sensor.
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Perform the
Diagnostic Repair Verification
after completing the diagnostic procedure.
