Range Inhibit or No Forward, Reverse with No Codes - keywords allison first lct1000 movement

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in the PI.

No reverse and may or may not move forward after a cold start. No DTCs will be set and may or may not show a range inhibit message.

Capture a Tech II or VDR snapshot of the concern and look at the ignition 0 voltage during the concern. If the voltage is less then 12 volts, inspect circuit 1020 for the cause of the low voltage. A weak battery in a diesel application or a poor connection at the ignition switch are possible areas to inspect.

Please follow this diagnosis process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.