GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Saturn 🢒 2004 🢒 ION 🢒 Transmission/Transaxle 🢒 Automatic Transaxle - AF23-5 🢒 DTC P0601, P0602, P0603, or P0604

Circuit Description

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

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 requests the engine control module (ECM) to illuminate the malfunction indicator lamp (MIL).
    • The TCM allows the vehicle to operate in transmission protection mode.
    • The TCM records the operating conditions when the Conditions for Setting the DTC are met. The TCM stores this information as a Failure Record.
    • The ECM records the operating conditions when the Conditions for Setting the DTC are met. The ECM stores this information as a Freeze Frame.

Conditions for Clearing the DTC
    • The ECM turns off the MIL after the third consecutive drive trip in which the TCM does not send a MIL illumination request.
    • A scan tool can clear the DTC.
    • The TCM clears the DTC from TCM history if the vehicle completes 40 warm-up cycles without an 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-Engine Controls?

Go to Step 2

Go to Diagnostic System Check - Engine Controls in Engine Controls - 2.2L (L61)

2

Is DTC P0602 set?

Go to Step 3

Go to Step 5

3

Program the TCM. Refer to Transmission Control Module Reprogramming .

Does DTC P0602 reset?

Go to Step 4

Go to Step 6

4
  1. Ensure that all tool connections are secure.
  2. Ensure the programming equipment is operating correctly.
  3. Ensure the correct software/calibration package is used.
  4. Attempt to program the TCM. Refer to Transmission Control Module Reprogramming .

Does DTC P0602 reset?

Go to Step 5

Go to Step 6

5

Replace the TCM. Refer to Transmission Control Module Replacement .

Did you complete the replacement?

Go to Step 6

--

6

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 7

Go to Step 2

7

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 in Engine Controls - 2.2L (L61)

System OK