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Test Description

WARNING: This page is about a different car, the 2004 GMC Sierra and 2004 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.

The numbers below refer to the step numbers on the diagnostic table.

  1. 2:  This step ensures the malfunction is present.
  2. 3:  This step tests the KS for proper operation.
  3. 6:  If the KS signal wire is shorted to ground or is shorted to voltage, the KS may still produce a signal.
  4. 7:  If the KS low reference is shorted to ground or is shorted to voltage, the KS may still produce a signal.
DTC P0327

Step Action Yes No
Schematic Reference:  Engine Controls Schematics 
Connector End View Reference:  Engine Controls Connector End Views  or  Powertrain Control Module (PCM) Connector End Views 
1 Did you perform the Diagnostic System Check-Engine Controls? Go to Step 2  Go to Diagnostic System Check - Engine Controls
2 
    IMPORTANT: If an engine knock can be heard, repair the engine mechanical condition before proceeding with this diagnostic. Refer to Symptoms - Engine Mechanical in Engine Mechanical - 4.3L.
  1. Observe the Freeze Frame/Failure Records data for this DTC.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. 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.
Does the DTC fail this ignition?		 Go to Step 3  Go to Diagnostic Aids
3 
  1. Turn OFF the ignition.
  2. Disconnect the PCM.
  3. Connect a DMM between the KS signal circuit and the KS low reference circuit at the PCM connector.
  4. Set the DMM to the 400 mV AC hertz scale. Refer to Measuring Frequency in Wiring Systems.
    5. IMPORTANT: Do not tap on plastic engine components.
  5. Tap on the engine block near the KS while observing the signal indicated on the DMM.
Does the DMM display a fluctuating frequency while tapping on the engine block?		 Go to Step 6  Go to Step 4 
4
  1. Disconnect the KS.
  2. Test the KS signal circuit and the KS low reference circuit for an open or a high resistance. Refer to Testing for Continuity in Wiring Systems.
Did you find and correct the condition?		 Go to Step 12  Go to Step 5 
5 Test the KS signal circuit for a short to the KS low reference circuit. Refer to Testing for Short to Ground and Testing for a Short to Voltage in Wiring Systems.
Did you find and correct the condition?		 Go to Step 12  Go to Step 8 
6  Test the KS signal circuit for a short to ground and for a short to voltage. Refer to Testing for Short to Ground and Testing for a Short to Voltage in Wiring Systems.
Did you find and correct the condition?		 Go to Step 12  Go to Step 7 
7  Test the KS low reference circuit for a short to ground and for a short to voltage. Refer to Testing for Short to Ground and Testing for a Short to Voltage in Wiring Systems.
Did you find and correct the condition?		 Go to Step 12  Go to Step 9 
8 Test for an intermittent and for a poor connection at the KS. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.
Did you find and correct the condition?		 Go to Step 12  Go to Step 10 
9 Test for an intermittent and for a poor connection at the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.
Did you find and correct the condition?		 Go to Step 12  Go to Step 11 
10 Replace the KS. Refer to Knock Sensor (KS) Replacement .
Did you complete the replacement?		 Go to Step 12  -
11 Replace the PCM. Refer to Powertrain Control Module (PCM) Replacement .
Did you complete the replacement?		 Go to Step 12  -
12
  1. Clear the DTCs with a scan tool.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. 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.
Does the DTC fail this ignition?		 Go to Step 2  Go to Step 13 
13 Observe the Capture Info with a scan tool.
Are there any DTCs that have not been diagnosed?		 Go to Diagnostic Trouble Code (DTC) List System OK
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