Possible causes

– Transmission Control Relay harness is open or shorted
– Transmission Control Relay circuit poor electrical connection
– Faulty Transmission Control Relay
– Faulty Transmission Solenoid/Pressure Switch Assembly

Symptoms

– Engine Light ON (or Service Engine Soon Warning Light)

P0888 JEEP Description

The Transmission Control Module (TCM) has detected less than 3 volts at the Transmission Control Relay output circuit