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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 1472 (Engine Control System - Diagnosis - 4.2L (DTC P0140 To DTC P0506)) >> Diagnosis >> DTC P0327 or P0332 >> Test Description

Test Description

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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 or P0332

Step Action Values Yes No
Schematic Reference:  Engine Controls Schematics 
Connector End View Reference: Powertrain Control Module (PCM) Connector End Views  or  Engine Controls 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 mechanical noise can be heard, repair the condition before proceeding with this diagnostic. Refer to Symptoms - Engine Mechanical in Engine Mechanical - 4.2L.
  1. Observe the Freeze Frame/Failure Records data for this DTC.
  2. Turn the ignition OFF 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 affected KS.
  3. Set the DMM to the ohm scale.
  4. Measure the resistance from the signal terminal on the KS to a good ground with the DMM.
  5. Measure the resistance from the low reference terminal on the KS to a good ground with the DMM.
Does the DMM display OL for both terminals?		 - Go to Step 4  Go to Step 10 
4 
  1. Connect the DMM between the terminals of the affected KS.
  2. Set the DMM to the 400 mV AC hertz scale and wait for the DMM to stabilize at 0 Hz. Refer to Measuring Frequency in Wiring Systems.
    3. IMPORTANT: Do not tap on plastic engine components.
  3. Tap on the engine block with a non-metallic object near the affected 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 5  Go to Step 10 
5 
  1. Turn ON the ignition, with the engine OFF.
  2. Measure the voltage at the KS signal circuit to a good ground with a DMM.
  3. Measure the voltage at the KS low reference circuit to a good ground with a DMM.
Does the DMM display a voltage above the specified value on either circuit?		 1 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 or the KS low reference circuit for a short to voltage. Refer to Testing for a Short to Voltage andWiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 12  Go to Step 11 
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, and for a short to ground. Refer to Testing for Continuity ,Testing for Short to Ground 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 affected 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 affected 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 the ignition OFF 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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