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.

3: This step tests for a TCC release switch status change when the engine is running. If TCC release oil is present, the switch should be open.
4: If you disconnect the AT inline 20-way connector, the TCM should recognize an open TCC release switch. This indicates the wiring from the AT inline 20-way connector to the TCM is good.
7: This step ensures that the TCC release switch is in proper operating condition.
8: This step tests the TCC circuit for a mechanical or hydraulic condition.

DTC P0742

Step	Action	Yes	No
1	Did you perform the Diagnostic System Check - Vehicle?	Go to Step 2	Go to Diagnostic System Check - Vehicle
2	Install a 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. Using the Clear Info function erases the Freeze Frame and Failure Records from both the ECM and the TCM. Record the DTC Freeze Frame and Failure Records. Clear the DTC. Select TCC Release Pressure on the scan tool. Does the scan tool indicate TCC release pressure is present?	Go to Diagnostic Aids	Go to Step 3
3	Start the engine. Does the scan tool indicate TCC release pressure is present?	Go to Step 8	Go to Step 4
4	Turn OFF the ignition. Disconnect the AT inline 20-way connector. Additional DTCs may set. Turn ON the ignition, with the engine OFF. Does the scan tool indicate TCC release pressure is present?	Go to Step 6	Go to Step 5
5	Test the signal circuit of the TCC release switch for a short to ground between the TCM connector C2 and the AT inline 20-way connector. Refer to Testing for Short to Ground and Wiring Repairs . Did you find and correct the condition?	Go to Step 12	Go to Step 11
6	Test the signal circuit of the TCC release switch for a short to ground between the AT inline 20-way connector and the TFP manual valve position switch. Refer to Testing for Short to Ground and Wiring Repairs . Did you find the condition?	Go to Step 10	Go to Step 7
7	Remove the TFP manual valve position switch. Inspect the TCC release switch for the following conditions: A damaged or leaking seal Sediment or debris in the switch Damaged switch contacts Stuck switch contacts Did you find a condition?	Go to Step 9	Go to Step 8
8	Inspect for the following conditions: The TCC PWM solenoid valve for the fluid exhaust being restricted The TCC regulated apply valve for being stuck in the TCC apply position The TCC control valve for being stuck in the TCC apply position The TCC feed limit valve for being stuck This causes the TCC feed limit pressure, and the TCC release pressure to be low or nonexistent. The pressure regulator valve for being stuck The TCC fluid circuits for leaks Repair any of the above conditions as necessary. Refer to Control Valve Body Disassemble . Did you complete the repair?	Go to Step 12	-
9	Replace the TFP manual valve position switch. Refer to Transmission Fluid Pressure (TFP) Manual Valve Position Switch Replacement . Did you complete the replacement?	Go to Step 12	-
10	Replace the automatic transmission wiring harness. Refer to Wiring Harness Replacement . Did you complete the replacement?	Go to Step 12	-
11	Replace the TCM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement?	Go to Step 12	-
12	Perform the following procedure in order to verify the repair: Select DTC. Select Clear Info. Operate the vehicle under the following conditions: Start the engine. TCC release pressure must be present for 3 seconds. Select Specific DTC. Enter DTC P0742. Has the test run and passed?	Go to Step 13	Go to Step 2
13	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