P0846
Transmission Fluid Pressure Sensor/Switch B Circuit Range/Performance
Transmission controls
Generic OBD-II
Medium
What it means
P0846 means fluid-pressure sensor/switch 'B' is reporting a pressure that's outside the expected range or not changing as it should. It usually points to low fluid, a wiring problem, or a failing sensor rather than internal transmission damage. The engine starts and runs normally, but shifting can be harsh until it's repaired.
Medium
Can I keep driving? Usually — but harsh or delayed shifting and possible limp mode mean you should get it checked soon.
Common symptoms
What you'll notice
- Check-engine light on
- Harsh, delayed, or slipping shifts
- Erratic shift behavior
- Transmission may enter limp mode
Common causes
Most likely first
- Low or degraded transmission fluidLikely
- Faulty fluid pressure sensor/switch 'B' (out-of-range reading)Common
- Wiring or connector problems at the sensorCommon
- Sticking pressure control solenoid / valve bodyLess often
- Faulty transmission control module (TCM) — least likelyLess often
How to diagnose & fix
Work through it in order
- Check fluid level and condition; correct before deeper diagnosis.
- Inspect sensor 'B' wiring and connector for damage or corrosion.
- Compare the sensor's reading to actual line pressure with a gauge.
- Test the sensor's resistance/signal against spec; replace if out of range.
- If the sensor is good, inspect the valve body/solenoid. Clear and re-test.
FAQ
Quick answers
Is it safe to drive with P0846?+
The engine runs normally, but shifting can be harsh or unpredictable and the transmission may enter limp mode. Get it checked soon to rule out low fluid or a pressure problem.
Can I just clear P0846?+
It comes back until the underlying fluid, wiring, or sensor fault is repaired.
Related codes
Often seen with P0846
Read & clear P0846 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