Possible causes

– OD Pressure Switch harness is open or shorted
– OD Pressure Switch circuit poor electrical connection
– Faulty OD Pressure Switch
– 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 P0871

Symptoms

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

P0871 JEEP Description

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

JEEP Technical Service Bulletins for P0871 code