Transmission Fluid Pressure Sensor/Switch D Circuit Intermittent
The P0879 code means the vehicle's onboard diagnostic system has detected: Transmission Fluid Pressure Sensor/Switch D Circuit Intermittent. This is a moderate severity code.
- Keep driving?
- Short distances only
- DIY difficulty
- hard
- Estimated cost
- $100 - $500 (parts and labor)
Read and clear transmission codes. Many trans codes are caused by low or burnt fluid -- check level and color before assuming the worst.
Basic scanners only read engine codes. This reads transmission, ABS, and airbag too.
Affiliate links — we earn a commission at no extra cost to you.
What Are the Symptoms of P0879?
- Check Engine Light illuminated intermittently
- Occasional shift quality issues
- Sporadic transmission warning light
- Shifting inconsistency that comes and goes
What Causes P0879? (Most Likely First)
- Loose connector at pressure sensor D Very High
- Intermittent break in sensor D wiring High
- Sensor D internal failure with sporadic output Moderate
- Vibration-induced wiring fault near transmission Moderate
Can I Still Drive with P0879?
Short distances only. P0879 is rated moderate severity. Keep trips short and get it diagnosed soon rather than waiting for symptoms to worsen.
Frequently Asked Questions
How do I catch an intermittent sensor D fault?
Use a scan tool with data logging capability to record sensor D readings over multiple drive cycles. Review the data for sudden dropouts or spikes.
Can tightening the connector fix the code?
If the connector is loose, firmly reseating it and applying dielectric grease may resolve the intermittent connection. Clear the code and monitor.
Should I replace the sensor if the code keeps returning?
If the wiring and connector are confirmed good after thorough inspection, replacing the sensor is the next logical step.
Mechanics Guide Step-by-step diagnosis
How Do You Diagnose P0879?
-
Wiggle test on sensor D connector while monitoring live data
-
Inspect wiring harness for chafing near transmission mounting points
-
Data-log sensor D readings over several drive cycles
-
Check connector pins for signs of corrosion or looseness
Sources 2
This page is built from documented references. Verify against your own service info before repair work.
- SAE J2012Diagnostic Trouble Code Definitions (defines the generic OBD-II code ranges)
- Cross-checked against the SAE J2012:2002 DTC table (2026-08-27)archived scan of the SAE standard — readable copy, not SAE’s current edition
Which Vehicles Commonly Get P0879?
- 2017-2020 Ford Expedition (10R80)
- 2015-2019 GM Sierra (8L90)
- 2014-2020 Jeep Cherokee (ZF 9HP)
- 2016-2020 Toyota Tacoma
Explore More
Was this helpful?
Send this to whoever is fixing the car — your mechanic, or the person asking what the light means.