Allison Transmission 1000/2000 Operator`s Manual

NOTE: (Only SEM or LRTP equipped vehicles will be able to offer torque limits. Otherwise, only the range inhibit light will be flashed.)

3.10 CHECK TRANS OR MALFUNCTION INDICATOR LIGHT

(MIL)

The red or amber CHECK TRANS indicator or Malfunction Indicator Light

(MIL) is located on the dash panel. A MIL is present on vehicles that meet industry On­Board Diagnostics II (OBD II) requirements. A CHECK TRANS indicator is present on vehicles not subject to industry OBD II requirements.

Each time the engine is started, the CHECK TRANS indicator or MIL will illuminate, then turn off after two seconds. If the indicator does not illuminate during ignition, or if the indicator remains on after ignition, the transmission system should be checked immediately.

Illumination of the MIL or CHECK TRANS indicator at any time after start­up indicates that a problem has been detected. The TCM will register a DTC and shifts may be restricted. Depending upon the severity of the problem, operation may continue in order to reach service assistance. The TCM may not respond to shift selector requests since upshifts and downshifts may be restricted and direction changes may not occur.

Illumination of the MIL or CHECK TRANS indicator at any time after start­up may indicate a problem with the engine or transmission, refer to the

6.0 DIAGNOSTICS

section for more information on diagnostic codes.

CAUTION: Do not drive the vehicle for any longer than one­half hour after the MIL or CHECK TRANS indicator illuminates. Continued operation of the vehicle for more than thirty minutes after the Check

Trans or Malfunction Indicator Light illuminates is not recommended.

This thirty­minute window is intended to allow the operator to reach service assistance.

3.11 DIAGNOSTIC CODES OVERVIEW

Refer to detailed information in the

6.0 DIAGNOSTICS

section.

3.12 SHIFT INHIBITS

The transmission control system inhibits shifting to protect the transmission from some types of abusive operation, in response to Diagnostic Trouble

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