Possible causes

– Faulty Pressure Switch Rationality
– Pressure Switch Rationality harness is open or shorted
– Pressure Switch Rationality circuit poor electrical connection
– Internal transmission damage
– Faulty Engine Control Module (ECM)
– Faulty Transmission Control Module (TCM)

Tech notes

There is a factory service bulletin for the following Jeep models:

2003-2005 Jeep Wrangler
2003-2005 Jeep Liberty
2003-2005 Jeep Cherokee

Jeep Factory Service Bulletin OBDII Code P0846

Symptoms

– Engine Light ON (or Service Engine Soon Warning Light)
– Transmission will not shift gears.

P0846 JEEP Description

The Transmission Control Module (TCM) has detected a fault in the pressure switch assembly

JEEP Technical Service Bulletins for P0846 code