2010 Cadillac Truck SRX AWD V6-2.8L Turbo Page 1260
DTC P0324 (LAU)
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic System
Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Strategy Based Diagnosis) for an
overview of the diagnostic approach.
* Diagnostic Procedure Instructions (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic Procedure
Instructions) provides an overview of each diagnostic category.
DTC Descriptors
DTC P0324
- Knock Sensor Module Performance
Circuit/System Description
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.
The ECM tests the functionality of the internal knock sensor signal evaluation circuitry. The knock sensor circuitry within the ECM is responsible
for receiving, amplifying, filtering, and evaluating the AC voltage and frequency from the knock sensors. The ECM performs two tests that
determine if the internal circuitry within the ECM is functioning correctly.
Test One
The ECM internally turns OFF the knock sensor signal circuits. The ECM then applies different test signals to the internal knock sensor circuitry to
verify that each test signal output response is within range. If the ECM detects that any of the test signals are not within range, this DTC sets.
Test Two
The ECM internally turns OFF the knock sensor signal circuits. The ECM then tests for any output response when no test signals are applied. If the
ECM detects an output response, this DTC sets.
Test Three
The ECM internally turns OFF the knock sensor signal circuits. The ECM generates an internal test pulse and monitors the return signal. If the
return test pulse is less than a calibrated threshold, this DTC sets.
Conditions for Running the DTC
* The ECM is controlling spark.
* The engine coolant temperature is warmer than 45掳C (113掳F).
* DTC P0324 runs continuously once the above conditions are met.
Conditions for Setting the DTC
* The ECM detects an incorrect response to the self tests performed on the internal knock sensor circuitry.
* The condition exists for greater than 1 s or for a cumulative of 10 s.
Action Taken When the DTC Sets
DTCs P0324 is a Type B DTC.
Conditions for Clearing the DTC
DTCs P0324 is a Type B DTC.
Reference Information
Description and Operation
Knock Sensor System Description (See: Powertrain Management/Computers and Control Systems/Knock Sensor/Description and Operation)
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions (See: Diagnostic Trouble Code Descriptions/Powertrain Diagnostic Trouble Code
