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Home >> Cadillac >> 2006 >> STS Base, 3.6 7, RWD >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 11 (Engine Control System - 4.6L (LH2) - DTC P0135 To P0391) >> DTC P0325 or P0330 >> Test Description

Test Description

WARNING: This page is about a different variant/trim than selected.

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

  1. 5:  If the KS signal circuit or the KS low reference circuit is shorted to voltage, the KS may still produce a signal.
  2. 6:  If the KS signal circuit or the KS low reference circuit is shorted to ground, the KS may still produce a signal.
DTC P0325 or P0330

Step Action Yes No
Schematic Reference: Engine Controls Schematics
Connector End View Reference: Engine Control Module 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 - 4.6L.
  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 engine control module (ECM).
  3. Connect a DMM between the affected knock sensor (KS) signal circuit and the KS low reference circuit.
  4. 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.
    5. IMPORTANT: Do not tap on plastic engine components.
  5. Observe the DMM while tapping on the engine block with a non-metallic object.
Does the DMM display a fluctuating frequency while tapping on the engine block?		 Go to Step 4  Go to Step 7 
4
  1. Set the DMM to the ohm scale.
  2. Measure the resistance from the KS signal circuit to a good ground with the DMM.
  3. Measure the resistance from the KS low reference circuit to a good ground with the DMM.
Does the DMM read OL?		 Go to Step 5  Go to Step 6 
5 
IMPORTANT: Disconnection of the ECM during testing may eliminate the voltage source that caused this fault.
Test the affected KS signal circuit or the KS low reference circuit for a short to power or a short to another ECM circuit.Did you find and correct the condition?		 Go to Step 14  Go to Step 11 
6 
IMPORTANT: Disconnection of the ECM during testing may eliminate the ground source that caused this fault.
Test the KS signal circuit or the KS low reference circuit for a short to ground or a short to another ECM circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.Did you find and correct the condition?		 Go to Step 14  Go to Step 11 
7
  1. Remove the fuel injector sight shield. Refer to Fuel Injector Sight Shield Replacement in Engine Mechanical - 4.6L.
  2. Disconnect the 12-way connector at the right rear of the engine.
  3. Test the affected KS signal circuit and the KS low reference circuit between the 12-way connector and the ECM for the following conditions:
    • An open
    • A high resistance
    • The signal circuit and low reference circuit shorted together

      Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?		 Go to Step 14  Go to Step 8 
8 Test for an intermittent and for a poor connection at the 12-way connector. 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 14  Go to Step 9 
9
  1. Remove the intake manifold. Refer to Intake Manifold Replacement in Engine Mechanical - 4.6L.
  2. Test the affected KS signal circuit and the KS low reference circuit between the 12-way connector and the KS for the following conditions:
    • An open
    • A high resistance
    • The signal circuit and low reference circuit shorted together

      Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?		 Go to Step 14  Go to Step 10 
10 Test for an intermittent and for a poor connection at the affected KS. Refer to Testing for Intermittent Conditions and Poor Connections andConnector Repairs in Wiring Systems.
Did you find and correct the condition?		 Go to Step 14  Go to Step 12 
11 Test for an intermittent and for a poor connection at the ECM. 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 14  Go to Step 13 
12 Replace the affected KS. Refer to Knock Sensor 1 Replacement or Knock Sensor 2 Replacement .
Did you complete the replacement?		 Go to Step 14  -
13 Replace the ECM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.
Did you complete the replacement?		 Go to Step 14  -
14
  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 15 
15 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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