When the ignition is turned on and the transmission control module (TCM) is powered up or when DTCs are cleared, the TCM performs a self-test to determine if the calibration is valid.
DTC P0602 is a type C DTC.
This diagnostic procedure supports the following DTC:
DTC P0602 Transmission Control Module (TCM) Not Programmed
• | The components are powered and ignition voltage is greater than 9.0 volts and less than 18 volts. |
• | This test will run before any TCM function. |
DTC P0602 sets if the TCM determines the present calibration is invalid.
• | The TCM does not illuminate the malfunction indicator lamp (MIL). |
• | The transmission is limited to forward range, due to presence of default calibration. |
• | The TCM returns to the boot program, and then waits to be calibrated. |
• | The TCM inhibits torque converter clutch (TCC) engagement. |
The TCM must be calibrated.
DTC P0602 may set because of improper TCM reprogramming.
Step | Action | Yes | No |
---|---|---|---|
Schematic Reference: Automatic Transmission Controls Schematics | |||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | |
2 |
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. Did DTC P0602 set again? | Go to Step 3 | Go to Diagnostic Aids |
3 | Perform the transmission control module programming procedure. Refer to Control Module References for replacement, setup, and programming. Did DTC P0602 set again? | Go to Step 4 | Go to Step 5 |
4 |
Important: In most cases, the TCM is not at fault. Investigate thoroughly before replacing the TCM. 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 procedure in order to verify the repair:
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 DTCs that you have not diagnosed? | System OK |