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Home >> Chevrolet >> 2005 >> Classic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System (DTC P0301-P2401) >> Diagnostic Information & Procedures >> DTC P0327 >> Test Description
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Test Description

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

  1. 2:  This step ensures that the malfunction is present.
  2. 3:  This step tests for a KS that is shorted to ground.
  3. 4:  This step tests the KS for proper operation.
  4. 5:  This step tests for a short to voltage on the KS signal circuit and the KS low reference circuit.
DTC P0327

Step Action Values Yes No
Schematic Reference: Engine Controls Schematics
Connect End View Reference: Powertrain Control Module (PCM) Connector End Views or Engine Controls Connector End Views
1 Did you perform the Diagnostic System Check - Vehicle? - Go to Step 2  Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2 
IMPORTANT: If an engine mechanical noise can be heard, repair the condition before proceeding with this diagnostic. Refer to Symptoms - Engine Mechanical in Engine Mechanical - 2.2L.
  1. Observe the Freeze Frame/Failure Records 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 knock sensor (KS).
  3. Set the DMM to the ohm scale.
  4. Measure the resistance from the KS signal circuit on the sensor side of the KS harness connector to a good ground with the DMM.
  5. Measure the resistance from the KS low reference circuit on the sensor side of the KS harness connector to a good ground with the DMM.
Does the DMM display OL for both circuits?		 - Go to Step 4  Go to Step 8 
4 
    IMPORTANT: Do not route the DMM leads near an ignition control device or an incorrect reading may result.
  1. Connect a DMM between the signal circuit of the KS and the low reference circuit of the KS on the sensor side of the KS harness connector.
  2. Set the DMM to the AC scale.
  3. Start the engine.
  4. Idle the engine for 2 minutes with the engine coolant temperature (ECT) above 82° C (180° F).
  5. Observe the DMM while accelerating the engine from idle to 3,000 RPM.
Is the voltage below the first specified value at idle and above the second specified value at 3,000 RPM?		 20 mV
80 mV		 Go to Step 5  Go to Step 8 
5 
  1. Turn ON the ignition, with the engine OFF.
  2. Set the DMM to the DC scale.
  3. On the powertrain control module (PCM) side of the KS harness connector, measure the voltage from the KS signal circuit to a good ground with a DMM.
  4. On the PCM side of the KS harness connector, measure the voltage from the KS low reference circuit to a good ground with a DMM.
Is the voltage more than the specified value on any circuit?		 4.5 V Go to Step 6  Go to Step 7 
6
  1. Turn OFF the ignition.
  2. Disconnect the PCM.
  3. Test the KS signal circuit and the KS low reference circuit for a short to voltage. Refer to Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 12  Go to Step 9 
7
  1. Turn OFF the ignition.
  2. Disconnect the PCM.
  3. Test the KS signal circuit and the KS low reference circuit for an open, for a high resistance, or for a short to ground. Refer to Circuit Testing and Wiring Repairs 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 Control Module References in Computer/Integrating Systems for replacement, setup, and programming.
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 - Vehicle in Vehicle DTC Information System OK
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