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Home >> GMC >> 2006 >> Sierra 1500 HD, RWD >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 29 (Automatic Transmission - 4L60-E/4L65-E/4L70-E - DTC P0218 To DTC P0785) >> DTC P0756 >> 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. 2:  This step tests that the PCM commanded all shifts, that all shift solenoid valves responded correctly, but that all the shifts did not occur.
DTC P0756

Step Action Values 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 Freeze Frame and Failure Records. Using the Clear Info function erases the Freeze Frame and Failure Records from the PCM.
  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 PCM commands 1st, 2nd, 3rd and 4th gears.

Did you detect a 4-3-3-4 shift pattern?		 - Go to Step 3  Go to Diagnostic Aids 
3
  1. Inspect the shift solenoid/hydraulic circuit for the following conditions:
    • Debris or chips in the AFL oil passage.
    • Debris or chips restricting oil flow in passage #29 of the case or through the spacer plate gasket into the valve body.
    • A cracked 2-3 shift solenoid.
    • A 2-3 shift valve which is stuck or hung up in the valve body bore.
    • A 2-3 shuttle valve which is stuck or hung up in its bore.
    • Damaged seals on the shift solenoid valves.

      Refer to Shift Solenoid Leak Test .

  2. Clean and inspect the related valves, bores and the valve body for debris or contamination.
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. Drive the vehicle in D4 range under the following condition, only if traffic and road conditions permit:

    Hold the throttle at 40% and accelerate to 64 km/h (40 mph).

  4. Select Specific DTC.
  5. Enter DTC P0756.

Has the test run and passed?		 - 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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