Engine RPM too high

Reduce the engine RPM. It may be necessary to select Neutral, and then D or R again.

Low fluid level

Add the fluid to proper level Transmission Fluid Check .

Faulty throttle signal from engine

Correct the engine throttle signal.

Shift selector is not functioning properly

Repair the shift selector.

Speed sensor or sensors not functioning properly

Repair or replace the speed sensor or sensors or circuitry. Refer to Speed Sensor Replacement .

Mechanical failure to C5 clutch

Repair the transmission.

Mechanical failure in transmission torque converter, shafts, or planetaries

Repair the transmission.

Low pressure

Repair the transmission.

Faulty wiring in TCM input/output function circuits

Correct the circuit wiring.