For 1990-2009 cars

### Circuit Description

The internal fault detection is handled inside the transmission control module (TCM). No external circuits are involved.

DTC P0602 is a type C DTC.

### DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P0602 Transmission Control Module (TCM) Not Programmed

### Conditions for Running the DTC

The TCM runs the program to detect an internal fault when the engine is running. The only requirements are voltage and ground. This program runs even if the voltage is out of the valid operating range.

### Conditions for Setting the DTC

The TCM has detected an internal malfunction.

### Action Taken When the DTC Sets

• | The TCM records the operating conditions when the Conditions for Setting the DTC are met. The TCM stores this information as Failure Records.

• | The TCM stores DTC P0602 in TCM history.

### Conditions for Clearing the DTC

• | A scan tool can clear the DTC.

• | The TCM clears the DTC from TCM history if the vehicle completes 40 warm-up cycles without a non-emission-related diagnostic fault occurring.

• | The TCM cancels the DTC default actions when the ignition is OFF long enough in order to power down the TCM.

### Test Description

The number below refers to the step number on the diagnostic table.

1. A DTC P0602 indicates the TCM is not programmed.

Step | Action | Yes | No
--- | --- | --- | ---
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle
2 | Is DTC P0602 set? | Go to Step 3 | Go to Step 4
3 | Program the transmission control module (TCM). Refer to Control Module References for replacement, setup, and programming. Does DTC P0602 reset? | Go to Step 4 | Go to Step 5
4 | Replace the TCM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | Go to Step 5 | --
5 | Perform the following in order to verify the repair:

1. Select the DTC.
2. Select Clear Info.
3. Start the engine.
4. Select specific DTC, for the DTC that was set.

Has the test run and passed?

Go to Step 6

Go to Step 2

6 | With the scan tool, observe the stored information, capture info and DTC info. Does the scan tool display any DTC's that you have not diagnosed? | Go to Diagnostic Trouble Code (DTC) List - Vehicle | System OK