Allison 1000 & 2000 Gen 4 Fault Codes: P0602 TCM Not Programmed CIRCUIT DESCRIPTION:At the power up and after clearing codes, the Transmission Control Module (TCM) performs a self-test to determine if the calibration in memory is valid. CONDITIONS FOR RUNNING THE DTC:1. The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM) or greater than 18V and less than 32V (24V TCM).2. This test will run before any TCM functions. CONDITIONS FOR SETTING THE DTC:DTC P0602 sets if the TCM determines the present calibration is invalid. ACTION TAKEN WHEN THE DTC SETS:1....

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...

Allison 1000 & 2000 Gen 4 Fault Codes: P0614 Torque Control Data Mismatch – ECM/TCM CIRCUIT DESCRIPTION:Shift Energy Management (SEM) allows the Transmission Control Module (TCM) to request torque reduction from the engine controller. By reducing torque, shifts can be made quicker, at a more consistent output torque which reduces clutch temperatures and increases clutch life. When an engine torque rating exceeds 580 lb ft, Lower Range Torque Protection (LRTP) is used. This feature limits engine torque in lower ranges to protect the transmission from damage if a stall condition occurs. CONDITIONS FOR RUNNING THE DTC:1. No DTC U2105 CAN...

Allison 1000 & 2000 Gen 4 Fault Codes: P0701 Transmission Control System Performance CIRCUIT DESCRIPTION:The Transmission Control Module (TCM) monitors the status of the pressure switches at start-up to detect the presence of hydraulic pressure. CONDITIONS FOR RUNNING THE DTC:1. The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM).2. Engine speed is greater than 200 rpm and less than 7500 rpm for 5 seconds.3. This test is run after engine start-up and runs as part of the transmission hydraulic initialization. CONDITIONS FOR SETTING THE DTC:DTC P0701 sets when transmission fluid temperature is...

Allison 1000 & 2000 Gen 4 Fault Codes: P0703 Brake Switch Circuit Malfunction – GMT 800 Only CIRCUIT DESCRIPTION:A mechanical switch attached to the brake pedal sends a signal to the Transmission Control Module (TCM) indicating the service brake has been applied. This signal is either ignition voltage or a ground signal depending on the calibration installed in the TCM. P0703 is a type C DTC. CONDITIONS FOR RUNNING THE DTC:1. The components are powered and ignition voltage is greater than 9V and less than 18V (12V TCM).2. No DTC P0721 or P0722. CONDITIONS FOR SETTING THE DTC:The TCM sets...