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Home >> Chevrolet >> 2005 >> Classic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System (DTC P0301-P2401) >> Diagnostic Information & Procedures >> DTC P0340 >> Test Description
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Test Description

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

  1. 4:  This step determines if the ignition system is working correctly.
  2. 5:  This step determines if the interconnect is bad or if a poor connection exists between the ICM and the Coil Cassette.
DTC P0340

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
  1. Install the scan tool.
  2. Start and idle the engine.
  3. Monitor the CMP Active Counter parameter with the scan tool.
Does the scan tool indicate the CMP active counter is incrementing?		 - Go to Step 3  Go to Step 4 
3
  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.
Did the DTC fail this ignition?		 - Go to Step 4  Go to Diagnostic Aids
4 
  1. Turn OFF the ignition.
  2. Disconnect the ignition control module (ICM) electrical connector.
  3. Connect a jumper wire from each terminal, except the CMP signal circuit, in the ICM harness connector to the corresponding terminal at the ICM with the J 35616  Connector Test Adapter Kit.
  4. Measure the DC duty cycle between the camshaft position (CMP) signal circuit at the ICM and a good ground.
  5. Start the engine.
Is the duty cycle within the specified range?		 45-55% Go to Step 6  Go to Step 5 
5 
  1. Turn OFF the ignition.
  2. Remove the jumper wires from the ICM.
  3. Remove the ICM from the Ignition Coil Cassette. Refer to Ignition Control Module Replacement .
  4. Remove the interconnect from between the coil cassette and the ICM.
  5. Inspect the interconnect for a poor connection at the coil cassette or at the ICM.
Did you find and correct the condition?		 - Go to Step 11  Go to Step 7 
6 Test the CMP signal circuit for the following conditions:
  • An open
  • High resistance
  • A short to ground
  • A short to voltage

Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 11  Go to Step 8 
7 Test for an intermittent and for a poor connection at the ICM. 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 11  Go to Step 9 
8 Test for an intermittent and for a poor connection at the powertrain control module (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 11  Go to Step 10 
9 Replace the ICM. Refer to Ignition Control Module Replacement .
Did you complete the replacement?		 - Go to Step 11  -
10 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 11  -
11
  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.
Did the DTC fail this ignition?		 - Go to Step 2  Go to Step 12 
12 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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