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Home >> Chevrolet >> 2006 >> Silverado 1500 HD, 4WD >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 28 (AUTOMATIC TRANSMISSION - ALLISON - DIAGNOSTICS (DTCs P0218-P0731)) >> DTC P0727 >> 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 ignition voltage.
  2. 3:  This step tests the wiring at the TCM.
  3. 4:  This step tests engine speed sensor resistance.
DTC P0727

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. Using the scan tool, observe ignition voltage.
Is voltage within the specified range?		 9-18 V Go to Step 3  Go to DTC P0562  for low voltage or DTC P0563  for high voltage
3
  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. See Special Tools .
  4. Using the DMM, measure the resistance between connector terminals 39 and 59.
Is the speed sensor resistance within the specified value?		 2,600 ohm @ 25°C (77°F) Go to Diagnostic Aids Go to Step 4 
4
  1. Disconnect the wiring harness from the engine speed sensor.
  2. Using the DMM and the J 35616  GM terminal test kit, measure the resistance between the speed sensor terminals.
Is the speed sensor resistance within the specified value?		 2,600 ohm @ 25°C (77°F) Go to Step 5  Go to Step 6 
5 Test the engine speed sensor circuit between the TCM and engine speed sensor for an open or short to ground condition. Refer to Circuit Testing .
Did you find and correct the condition?		 - Go to Step 7  -
6
IMPORTANT: Do not rotate the speed sensor in the retaining bracket. Orientation is fixed, and if changed, may cause improper operation.
Replace the turbine speed sensor. Refer to Speed Sensor Replacement .Did you complete the replacement?		 - Go to Step 7  -
7 Perform the following procedure in order to verify the repair:
  1. Clear the DTC.
  2. Using the scan tool, monitor the engine speed sensor operation.
  3. Select Specific DTC.
  4. Enter DTC P0727.

Has the test run and passed?		 - Go to Step 8  Go to Step 2 
8 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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