BC. Transmission Emergency Modes

BC. Emergency programs

When there is a transmission malfunction registered by the transmission control module (TCM) an emergency program is activated to deal with the fault. The control system implements various corrective measures to protect the transmission, while at the same time attempting to leave the car in a driveable status. There are different programs depending on the control module and the type of malfunction detected.







Specifications for control modules GROUP I and II can be found in Description and Operation Control modules.


Emergency mode, (GROUP I control modules)

Flashing indicator and warning light on the instrument panel. There are exceptions. Refer to the table at D. Diagnostic Codes.) The transmission shifts gears, but the lock-up function is inoperable. D. Volvo Diagnostic Trouble Code Table

Maximum system pressure is reached (some faults), making shifting rough. The combination of lock-up inoperability and rough shifting indicates a fault in the electrical system.



Emergency mode I, (GROUP II control modules)

The transmission shifts but the transmission control module (TCM) does not send signals to the lock-up valve. Lock-up function inoperable.


Emergency mode II, (GROUP II control modules)

The transmission shifts but the transmission control module (TCM) does not send signals to the lock-up valve. Lock-up function inoperable. No reduction of system pressure when shifting, making shifting rough. No reduction of engine torque when shifting.

"Limp-home" mode

When the transmission control module (TCM) registers a serious malfunction in the transmission it activates the "Limp-home" mode emergency program. To protect the transmission the TCM cuts all power to the solenoids.

The indicator and warning light on the instrument panel flashes. The transmission will not shift gears, since no power is available to the solenoids. It operates only in 4th gear, position D and 3rd gear position L. Gear shifting can only be performed manually between 3rd and 4th gear, and position P R N D and L.

NOTE: When starting/driving, the gear selector should be set to position L to minimize wear on the transmission.