Allison 1000 & 2000 Gen 5 Fault Code:P0604 Control Module Random Access Memory (RAM)

CIRCUIT DESCRIPTION:
The Transmission Control Module (TCM) performs an internal memory self-test at power up that writes and reads patterns at specific RAM locations to verify that all addresses and data lines are functioning correctly.

ACTION TAKEN WHEN THE DTC SETS:
1. The CHECK TRANS light illuminates.
2. DTC is stored in the TCM history on next key cycle.
3. The TCM returns to the boot program.
4. The TCM inhibits shifts to range.

CONDITIONS FOR CLEARING THE DTC/CHECK TRANS LIGHT
Replace TCM.

DIAGNOSTIC AIDS:
Replace TCM.