P0879
Transmission Fluid Pressure Sensor/Switch D Circuit Intermittent
Transmission / fluid pressure
Generic OBD-II
Medium
What it means
P0879 means the transmission module is seeing an intermittent signal from fluid pressure sensor/switch D — the reading drops out or jumps unexpectedly rather than failing outright. The engine still starts and runs, but the sporadic signal can cause occasional harsh or erratic shifts and brief limp-mode episodes, usually pointing to a loose connection or chafed wire.
Medium
Can I keep driving? Usually driveable, but expect occasional harsh or delayed shifts and possible brief limp-mode episodes until the connection is fixed.
Common symptoms
What you'll notice
- Check-engine light that comes and goes
- Intermittent harsh, delayed, or erratic shifts
- Occasional slipping or sudden limp mode
- Symptoms that appear over bumps or when warm
Common causes
Most likely first
- Intermittent open or short in the sensor D wiringLikely
- Loose or corroded connector at the pressure sensorCommon
- Chafed harness that shorts intermittentlyCommon
- Faulty transmission fluid pressure sensor/switch DLess often
- Failed transmission control module (least likely)Less often
How to diagnose & fix
Work through it in order
- Read freeze-frame data, then wiggle-test the sensor connector and harness while watching live data for dropouts.
- Inspect the connector for corrosion, spread pins, or moisture and clean/repair as needed.
- Check the harness for chafing or pinch points along its routing.
- If the wiring is sound, replace the pressure sensor/switch D.
- Clear the code and road-test, including rough roads, to confirm the intermittent fault is gone.
FAQ
Quick answers
Is it safe to drive with P0879?+
Generally yes for short trips, but the intermittent signal can cause sudden harsh shifts or limp mode, so fix it before it becomes constant.
Can I just clear P0879?+
It may stay off briefly, but an intermittent wiring or sensor fault will trip it again until the root cause is repaired.
Related codes
Often seen with P0879
Read & clear P0879 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX