Allison 3000 & 4000 Gen 4 Fault Code: P0614 Torque Control Data Mismatch ECM/TCM

DIAGNOSTIC RESPONSE:
Allows operation only in reverse and second range

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 and at a more consistent output torque, which reduces clutch temperatures allowing increased clutch life. When an engine torque rating exceeds certain limits, Low 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.

This test detects:
1. If a high-rated engine (as determined by the selection of transmission calibration) supports SEM/LRTP as required.
2. If the engine rating (as broadcast by SAE J1939 Advertised Engine Torque Curve (AETC)) is acceptable for the transmission.

For high torque applications, the engine must support the required messages to allow SEM and LRTP. For low torque applications, SEM may or may not be active.

CONDITIONS FOR RUNNING THE DTC:
1. SEM and LRTP auto-detection logic runs during first 25 drive cycles with engine speed greater than 400 rpm.
2. SEM and LRTP auto-detection logic checks that all required parameters for SEM are present per OEM Tech Data, Engine Management SEM and LRTP-SAE J1939 Parameter AND SA use. If any indicate ‘Error’ or ‘Not Available’, then SEM is not enabled and TCM calibrations requiring SEM, will activate DTC P0614.
3. This test compares SAE J1939/71 AETC against the (SEM and non-SEM) maximum engine rating allowed for the transmission. If the TCM calibration does not require SEM/LRTP and if SAE J1939/71 AETC is not received, then this test will not execute.

NOTE: The autodetect drive cycles counter is reset to 0 after TCM recalibration or SEM Reset Auto-Select.

CONDITIONS FOR SETTING THE DTC:
After SEM and LRTP autodetect logic has counted 25 drive cycles, SEM is disabled and DTC P0614 sets during the following conditions:
1. Engine is not on SEM/LRTP approved list.
2. Engine and vehicle support all required SAE J1939 SEM or SEM/LRTP messages.
3. Engine does not respond as expected to transmission SEM torque reduction request message.
4. Engine does not respond as expected to transmission LRTP torque reduction request message.

ACTION TAKEN WHEN THE DTC SETS:
1. The CHECK TRANS light illuminates.
2. DTC is stored in the TCM history.
3. The TCM allows operation in Reverse (R), Neutral (N), and Second (2nd) range only.
4. The TCM freezes shift adapts (DNA).
5. The TCM inhibits TCC engagement.
6. DTCs P2637 and/or P2641 may also be active.

CONDITIONS FOR CLEARING THE DTC:
Use the diagnostic tool to clear the DTC from the TCM history. The TCM automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without the DTC recurring.

DIAGNOSTIC AIDS:
DTC P0614 may be caused by:
1. Incorrect engine calibration.
2. Incorrect transmission calibration.
3. Engine calibration that does not support all required SAE J1939 SEM/LRTP messages.
4. Communication link problem.
5. Defective TCM.

Review applicable information in the OEM Technician’s Library, General Troubleshooting of Performance Complaints-Shift Selector Issues, Control System and Transmission Specifications, and other related information.