Allison 1000 & 2000 Gen 4 Fault Codes: P0606 Controller Internal Performance – Not Enabled for Pickups or Med Duty “04”
CIRCUIT DESCRIPTION:
The Transmission Control Module (TCM) completes numerous scheduled tasks during normal operation. If one of the scheduled tasks fails to complete within a specific time limit the TCM will re-attempt this task.
NOTE: The presence of DTC P0606 indicates a TCM software error has occurred and the OEM Transmission Service Department should be contacted.
CONDITIONS FOR RUNNING THE DTC:
The components are powered and ignition voltage is greater than 9V and less than 18V for a 12V TCM, or greater than 18V and less than 32V for a 24 V TCM.
This test is run during the entire ignition cycle.
CONDITIONS FOR SETTING THE DTC:
DTC P0606 sets if a task fails to complete after two consecutive attempts.
ACTION TAKEN WHEN THE DTC SETS:
1. When DTC P0606 is active, the transmission will lock in N (Neutral).
2. DTC P0606 is stored in the TCM history.
3. The CHECK TRANS light illuminates.
4. The TCM freezes shift adapts (DNA).
5. The TCM inhibits TCC engagement.
CONDITIONS FOR CLEARING THE DTC/CHECK TRANS LIGHT:
A Scan Tool can clear the code from the TCM history. The TCM automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.
DIAGNOSTIC AIDS:
None
