Circuit Description
The internal fault detection is handled inside the transmission control module (TCM). No external circuits are involved.
DTC P0601 is a type A DTC.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P0601 Transmission Control Module (TCM) Read Only Memory (ROM)
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 powertrain control module (PCM) to illuminate the mallfunction indicator lamp (MIL). |
| • | The TCM turns the transmission protection mode ON. |
| • | The transmission will operate in 5th gear when shifted into D and 2nd gear when shifted into L. |
| • | The line pressure is set to maximum. |
| • | The torque converter clutch (TCC) is disabled. |
| • | The TCM freezes the transmission adaptive functions. |
| • | The PCM records the operating conditions when the Conditions for Setting the DTC are met. The PCM stores this information as Freeze Frame and Failure Records. |
| • | 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 TCM stores DTC P0601 in TCM history. |
Conditions for Clearing the DTC
| • | The PCM 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 MIL/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.
Step | Action | Yes | No |
|---|---|---|---|
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 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:
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? | System OK |
