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.

5: This step tests the TCM response function.
6: This step tests the transmission wiring harness integrity.
7: This step tests and evaluates the internal wiring harness.
8: This step tests the PSM for a failed condition.

DTC P0875

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	Measure line pressure. Refer to Line Pressure Check Procedure . Is the line pressure within the specified value?	-	Go to Step 4	Go to Symptoms - Automatic Transmission
4	Install the scan tool. Turn ON the ignition, with the engine OFF. 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. Record the DTC Freeze Frame and Failure Records. Clear the DTC. Start the engine. Using the scan tool, monitor TFP Sw. R status. Does the scan tool indicate TFP SW. R status is OFF?	-	Go to Diagnostic Aids	Go to Step 5
5	Turn the ignition OFF. Disconnect C2 connector (RED) at the TCM. Install the J 39700 breakout box and the J 43799 breakout box adapter at C2 connector. Connect terminal 4 to a known good ground. Turn ON the ignition, with the engine OFF. Does the scan tool indicate TFP SW. R status is ON when grounded and OFF when open?	-	Go to Step 6	Go to Step 12
6	Turn the ignition OFF. Connect the C2 connector to the TCM. Disconnect the transmission 20-way connector. Connect terminal K at the transmission 20-way connector to a good ground. Turn the ignition ON. Does the scan tool indicate TFP SW. R status is ON when grounded and OFF when open?	-	Go to Step 7	Go to Step 11
7	Remove the oil pan. Refer to Oil Pan Replacement . Disconnect the internal wiring harness from the PSM and ground pin D to a known good ground. Does the scan tool indicate TFP SW. R status is ON when grounded and OFF when open?	-	Go to Step 8	Go to Step 10
8	Remove the PSM from the control valve body and leave the internal harness connected. Refer to Pressure Switch Manifold Replacement . Provide a ground connection from the PSM frame to either the control valve body or the transmission main case. Using the eraser of a pencil, push gently on the pressure switch R membrane. Does the scan tool indicate TFP SW. R status is ON when grounded and OFF when open?	-	Go to Diagnostic Aids	Go to Step 9
9	Replace the PSM. Refer to Pressure Switch Manifold Replacement . Did you complete the replacement?	-	Go to Step 13	-
10	Replace the internal wiring harness. Refer to Wiring Harness Replacement . Did you complete the replacement?	-	Go to Step 13	-
11	Repair the engine wiring harness circuit for an open or short. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair?	-	Go to Step 13	-
12	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 13	-
13	Perform the following procedure in order to verify the repair: Clear the DTC. Start the engine. Using the scan tool, monitor TFP SW. R status. Select Specific DTC. Enter DTC P0875. Has test run and passed?	-	System OK	Go to Step 1