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Home >> Pontiac >> 2007 >> G6 Base, 3.5 N >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System & Fuel System - 3.5L - DTC P0340 To DTC P2544 >> DTC P0851 >> Circuit Testing

Circuit Testing

Step Action Yes No
1 Did you perform the Diagnostic System Check - Vehicle? Go to Step 2 Go to Diagnostic Trouble Code (DTC) List - Vehicle
2
  1. Install a scan tool.
  2. Turn ON the ignition with the engine OFF.
    IMPORTANT:
    • Record the Failure Records before clearing the DTCs. Using the Clear Info function erases the Failure Records.
    • Using the Clear Info function erases stored DTCs in both the ECM and TCM.
  3. Record the DTC Failure Records.
  4. Clear the DTC.
Did you record TCM Failure Records for DTC U0073, U0100, U0121 or U0140?		 Go to Powertrain Diagnostic Trouble Code (DTC) Type Definitions Go to Step 3
3
  1. Turn ON the ignition with the engine OFF.
  2. Select Engine Data on the scan tool.
  3. Monitor the PNP Switch display on the scan tool.
  4. Shift the transmission from Park to Drive.
Does the PNP Switch display Park/Neutral?		 Go to Step 4 Go to Testing for Intermittent Conditions and Poor Connections
4 Disconnect the automatic transmission inline 20-way connector. Does the PNP Switch display Park/Neutral? Go to Step 6 Go to Step 5
5 Test the PNP Switch signal circuit for a short to ground between the automatic transmission inline 20-way connector and transmission internal mode switch. Refer to Testing for Short to Ground.
Did you find the condition?		 Go to Step 7 Go to Step 8
6 Test the PNP Switch signal circuit for a short to ground between the automatic transmission inline 20-way connector and the ECM. Refer to Testing for Short to Ground.
Did you find and correct the condition?		 Go to Step 10 Go to Step 9
7 Replace the automatic transmission wiring harness. Refer to Wiring Repairs .
Did you complete the replacement?		 Go to Step 10 -
8 Replace the transmission internal mode switch. Refer to Manual Shift Detent Lever with Shaft Position Switch Assembly Removal.
Is the action complete?		 Go to Step 10 -
9 Replace the ECM. Refer to Control Module References for replacement, setup and programming.
Is the action complete?		 Go to Step 10 -
10 Perform the following procedure to verify the repair:
  1. Select DTC.
  2. Select Clear DTC Information.
  3. Turn OFF the ignition for at least 30 seconds.
  4. Start the engine.
  5. Select Specific DTC.
  6. Enter DTC P0851.

Has the test run and passed?		 Go to Step 11 Go to Step 2
11 With the scan tool, observe the stored information, capture info and DTC info.
Does the scan tool display any DTCs that you have not diagnosed?		 Go to Diagnostic Trouble Code (DTC) List - Vehicle System OK
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