P0870 Jeep Grand Cherokee - Od Hydraulic Pressure Test | Step-by-Step Diagnosis

P0870 (Od Hydraulic Pressure Test) on a Jeep Grand Cherokee? This video walks through the complete 17-step factory diagnostic procedure with the wiring diagram and connector views - no guesswork, no parts cannon. When monitored: In any forward gear with engine speed above 1000 RPM shortly after a shift and every minute thereafter. Set condition: After a shift into a forward gear, with engine speed above 1000 RPM, the PCM momentarily turns on element pressure to the Clutch circuits that don't have pressure to identify the correct Pressure Switch closes. If the Pressure Switch does not close 2 times, the DTC sets. In this video: 1. Check For Related Dtcs 2. Check If DTC P0760 Is Present 3. Check For Other Dtcs 4. Check If DTC P0870 Is Current 5. Check Line Pressure 6. Check The Line Pressure Sensor Connection 7. Check The Line Pressure Sensor Operation 8. Check The (F856) 5-Volt Supply Circuit For An Open 9. Check The (F856) 5-Volt Supply Circuit For A Short To Ground 10. Compare Scan Tool To Pressure Gauge 11. Check PCM And Wiring 12. Check For Excessive Debris 13. Check The Od Hydraulic Clutch Circuit 14. Check The (T9) Od Pressure Switch Sense Circuit For An Open 15. Check The (T9) Od Pressure Switch Sense Circuit For A Short To Ground 16. Check The (T9) Od Pressure Switch Sense Circuit For A Short To Another Circuit 17. Check Wiring And Connectors Possible causes covered: Line Pressure Sensor; Transmission Fluid Contamination; Related Dtc's Present; Transmission Solenoid/Trs Assembly; Excessive Debris In Oil Pan; Poor Line Pressure Sensor Connection; (T9) Od Pressure Switch Sense Circuit Open; Related TCM Power Input Dtcs Present. Applies to the Jeep Grand Cherokee third generation (WK, 2005-2010) with the 3.7L V6, 4.7L V8 and 5.7L HEMI V8 (and SRT-8 6.1L). Much of the diagnostic logic is shared with the related Jeep Commander (XK) of the same era. This is general information for educational purposes - always confirm against the service information for your exact vehicle.