AF33-5 Automatic Transmission

DTC P0601, P0602, P0603, or P0604

Diagnostic Instructions
^ Perform the [Diagnostic System Check - Vehicle Diagnostic Information] prior to using this diagnostic procedure.
^ Review [Strategy Based Diagnosis] for an overview of the diagnostic approach. Strategy Based Diagnosis
^ [Diagnostic Procedure Instructions - Vehicle Diagnostic Information] provides an overview of each diagnostic category. Diagnostic Procedure Instructions - Vehicle Diagnostic Information

DTC Descriptor
DTC P0601 Control Module Read Only Memory (ROM)
DTC P0602 Control Module Not Programmed
DTC P0603 Control Module (TCM) Long Term Memory Reset
DTC P0604 Control Module Random Access Memory (RAM)

Circuit/System Description
This diagnostic applies to internal microprocessor integrity conditions within the transmission control module (TCM) system. This diagnostic also addresses if the TCM is not programmed.

Conditions for Running the DTC
^ The ignition is ON, or the engine is operating.
^ The DTCs run once an ignition cycle.

Conditions for Setting the DTC

DTC P0601
The TCM detects that the checksum calculation does not match the expected checksum.

DTC P0602
The TCM is identified as not programmed.

DTC P0603
The TCM detects an incorrect copy of non-volatile memory.

DTC P0604
The TCM detects a random access memory (RAM) read/write error.

Action Taken When the DTC Sets

DTC P0601 and P0602
^ DTCs P0601, and P0602 are Type A DTCs.
^ The transmission will operate in 5th gear in D range, 2nd gear in L range.

DTC P0603
^ DTC P0603 is a Type C DTC.
^ The TCM uses default EEPROM values.
^ The TCM disables engine start.

DTC P0604
DTC P0604 is a Type A DTC.

Conditions for Clearing the DTC
^ DTCs P0601, P0602, and P0604 are Type A DTCs.
^ DTC P0603 is a Type C DTC.

Circuit/System Verification
1. Ignition ON, observe the DTC information with a scan tool. Verify that DTC P0602 does not fail this ignition cycle.
> If DTC P0602 failed this ignition, reprogram the TCM. If DTC P0602 resets, replace the TCM.
2. Observe the DTC information with a scan tool. Verify that DTCs P0601, P0603, and P0604 do not set this ignition cycle.
> If any of the DTCs P0601, P0603, or P0604 are set this ignition cycle replace the TCM.

Repair Instructions
Always perform the [Diagnostic Repair Verification - Vehicle Diagnostic Information] after completing the diagnostic procedure.