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Home >> GMC >> 2006 >> Sierra 1500 HD, RWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 1055 (Automatic Transmission - ALLISON - DTC P0877 To DTC P2670) >> DTC P0880 >> Test Description

Test Description

WARNING: This page is about a different car, the 2008 GMC Sierra, 2008 GMC Cab & Chassis Sierra, 2008 Chevrolet Silverado, and 2008 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

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

  1. 2:  This step tests the system voltage.
  2. 4:  This step tests the vehicle charging system.
  3. 5:  This step tests the wiring harness for opens or shorts.
Step Action Value Yes No
Schematic Reference: Automatic Transmission Controls Schematics
1 Did you perform the Diagnostic System Check - Vehicle? - Go to Step 2  Go to Diagnostic System Check - Vehicle
2 
  1. Install the 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 for reference. The Clear Info function will erase the data.
  3. Record the DTC Freeze Frame and Failure Records.
  4. Clear the DTC.
    5. IMPORTANT: If other DTCs are present, refer to the applicable diagnostic tables before continuing.
  5. Using the DMM, measure and record the voltage at the battery terminals.
Is voltage within the specified value?		 B+ Go to Step 3  Go to Battery Inspection/Test
3 Start the engine and warm to normal operating temperature.
Is the Alternator/Check Engine lamp ON?		 - Go to Charging System Test Go to Step 4 
4 
  1. Increase the engine speed to 1,000-1,500 RPM.
  2. Observe the system voltage on the scan tool.
Is voltage within the specified range?		 13-15 V Go to Step 5  Go to Charging System Test
5 
  1. Turn the ignition OFF.
  2. Disconnect the 80-way connector at the TCM.
  3. Install the J 39700  breakout box, the J-47275  breakout box adapter and the J 47275-1 magnetic overlay.
  4. Turn the ignition ON, with the engine OFF.
  5. Using the DMM, measure the voltage between connector terminal 9 and terminal 63.
  6. Turn the ignition OFF.
  7. Measure the voltage between connector terminal 63 and terminal 69.
  8. Subtract the voltage reading obtained in sub-step 5 from the voltage reading obtained in sub-step 3.
Is the voltage greater than the specified value?		 0.5 V Go to Step 6  Go to Step 8 
6
  1. Turn the ignition ON, with the engine OFF.
  2. Using the DMM, measure the voltage between connector terminal 9 and terminal 10.
  3. Measure the voltage between connector terminal 9 and terminal 70.
  4. Turn the ignition OFF, monitoring the system voltage during shutdown.
Was a loss of voltage detected?		 - Go to Step 7  Go to Step 8 
7
  1. Inspect the transmission wiring harness assembly.
  2. Repair the transmission wiring harness assembly. Refer to Circuit Testing and Wiring Repairs .
Did you complete the repair?		 - Go to Step 9  -
8
IMPORTANT: In most cases, the TCM is not at fault. Investigate thoroughly before replacing the TCM. Swap the TCM with a known good TCM to confirm diagnosis.
Replace the TCM. Refer to Control Module References for replacement, setup, and programming.Did you complete the replacement?		 - Go to Step 9  -
9 Perform the following procedure in order to verify the repair:
  1. Clear the DTC.
  2. Using the scan tool, monitor system voltage.
  3. Select Specific DTC.
  4. Enter DTC P0880.

Has the test run and passed?		 - Go to Step 10  Go to Step 2 
10 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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