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Test Description

WARNING: This page is about a different car, the 2004 GMC Sierra, 2004 GMC Cab & Chassis Sierra, 2004 Chevrolet Silverado, and 2004 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. 4:  This step tests 5 volt reference.
  2. 6:  This step tests the TFT sensor and internal wiring harness.
  3. 7:  This step tests the resistance of the TFT sensor.
DTC P0712

Step Action Value Yes No
Schematic Reference: Automatic Transmission Controls Schematics
1 Did you perform the Diagnostic System Check - Automatic Transmission? - Go to Step 2  Go to Diagnostic System Check - Automatic Transmission
2 Measure the transmission fluid level. Refer to Transmission Fluid Checking Procedure .
Is the transmission fluid level correct?		 - Go to Step 3  Go to Transmission Fluid Checking Procedure
3
  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. Select TFT on the scan tool.
  6. Drive the vehicle and inspect for an unrealistic TFT reading.
Is the TFT reading at or below the specified value?		 -36°C (-32°F) Go to Step 4  Go to Diagnostic Aids
4 
  1. Turn the ignition OFF.
  2. Disconnect C2 connector (RED) at the TCM.
  3. Install the J 39700  breakout box and the J 43799  breakout box adapter at C2 connector.
  4. Turn ON the ignition, with the engine OFF.
  5. Using a DMM, measure voltage at C2 connector (RED) terminal 10 and terminal 20.
Is voltage within the specified value?		 5 V Go to Step 5  Go to Step 11 
5
  1. Turn the ignition OFF.
  2. Using a DMM, measure resistance at C2 connector (RED) terminal 10 and terminal 20.
Is the resistance within the specified value?		 3,490 ohm @ 20°C (68°F)
177.9 ohm @ 100°C (212°F)		 Go to Diagnostic Aids Go to Step 6 
6 
  1. Turn the ignition OFF.
  2. Disconnect the transmission 20-way connector.
  3. Using a DMM, measure resistance at the transmission side 20-way connector terminals G and H.
Is the resistance within the specified value?		 3,490 ohm @ 20°C (68°F)
177.9 ohm @ 100°C (212°F)		 Go to Step 8  Go to Step 7 
7 
  1. Remove the oil pan.
  2. Disconnect the PSM from the internal wiring harness.
  3. Using a DMM, measure PSM resistance at terminals E and F.
Is resistance within the specified value?		 3,490 ohm @ 20°C (68°F)
177.9 ohm @ 100°C (212°F)		 Go to Step 9  Go to Step 10 
8 Repair the engine wiring harness. Refer to Wiring Repairs in Wiring Systems.
Did you complete the repair?		 - Go to Step 12  -
9 Replace the automatic transmission internal harness. Refer to Wiring Harness Replacement .
Did you complete the replacement?		 - Go to Step 12  -
10 Replace the PSM. Refer to Pressure Switch Manifold Replacement .
Did you complete the replacement?		 - Go to Step 12  -
11
IMPORTANT: In most cases, the TCM is not at fault. Investigate thoroughly before replacing the TCM.
Replace the TCM. Refer to Transmission Control Module (TCM) Replacement .Did you complete the replacement?		 - Go to Step 12  -
12 Perform the following procedure in order to verify the repair:
  1. Clear the DTC.
  2. Using the scan tool, monitor the transmission fluid temperature.
  3. Drive the vehicle under normal operating conditions. Watch for significant changes in TFT.
  4. Select Specific DTC.
  5. Enter DTC P0712.

Has the test run and passed?		 - System OK Go to Step 1 
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