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Home >> Hummer >> 2008 >> H2 4D Utility Wagon >> Repair and Diagnosis >> External Pages >> Different car >> Section 143 (Automatic Transmission - 4L80-E/4L85-E - DTC P0218 To DTC P0976) >> DTC P0751 >> Test Description

Test Description

WARNING: This page is about a different car, the 2007 GMC Yukon XL and 2007 Chevrolet Suburban. However, it is still accessible from the selected car via links, so may be relevant.

The number below refers to the step number on the diagnostic table.

  1. 2:  This step tests that the TCM commanded all shifts, that all shift solenoid valves responded correctly, but that all the shifts did not occur.
DTC P0751

Step Action Value Yes No
1 Did you perform the Diagnostic System Check - Vehicle? - Go to Step 2  Go to Diagnostic System Check - Vehicle
2 
  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
    3. IMPORTANT: Before clearing the DTC, use the scan tool in order to record the ECM and TCM Freeze Frame and Failure Records. Using the Clear Info function erases the Freeze Frame and Failure Records from the ECM and TCM.
  3. Record the DTC Freeze Frame and Failure Records.
  4. Clear the DTC.
  5. Drive the vehicle in D4 range under the following conditions:

    Accelerate the vehicle, ensuring that the TCM commands 1st, 2nd, 3rd and 4th gears.

Did you detect a 2-2-3-3 shift pattern?		 - Go to Step 3  Go to Testing for Intermittent Conditions and Poor Connections
3
  1. Inspect the shift solenoid/hydraulic circuit for the following conditions:
  2. Clean and inspect the related valves, bores and the valve body for debris or contamination restricting valve movement. Refer to Control Valve Body Cleaning and Inspection .
Did you find and correct the condition?		 - Go to Step 4  -
4 Perform the following procedure in order to verify the repair:
  1. Select DTC.
  2. Select Clear Info.
  3. Operate the vehicle under the following conditions:
    • Drive the vehicle in D4.
    • Ensure that the gear ratios are as specified for 1st and 4th gear for 0.9 second or greater.
  4. Select Specific DTC.
  5. Enter DTC P0751.

Has the test run and passed?		 1st: 2.42:1 to 2.52:1
4th: 0.70:1 to 0.80:1		 Go to Step 5  Go to Step 2 
5 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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