P0994
Transmission Fluid Pressure Sensor/Switch F Circuit Low
Transmission
Generic OBD-II
Medium
What it means
P0994 means the transmission control module is reading an abnormally low voltage from fluid pressure sensor/switch 'F', which monitors hydraulic pressure inside the automatic transmission. It can be a wiring/sensor fault or a genuinely low pressure caused by low fluid. Symptoms are usually harsh or erratic shifts, and the transmission may limp. The engine starts and runs normally.
Medium
Can I keep driving? Usually drivable, but shifts may be harsh or erratic and the transmission may limp; have it checked before long trips.
Common symptoms
What you'll notice
- Check-engine light on
- Harsh, delayed, or erratic shifting
- Poor acceleration or transmission slipping
- Transmission stuck in limp mode
Common causes
Most likely first
- Faulty transmission fluid pressure sensor/switch 'F'Likely
- Low or contaminated transmission fluidCommon
- Loose or corroded connector / short-to-ground in the sensor circuitCommon
- Damaged or frayed wiring in the circuitLess often
- Faulty transmission control module (TCM)Less often
How to diagnose & fix
Work through it in order
- Check transmission fluid level and condition first, since low fluid can cause genuinely low pressure readings.
- Read freeze-frame data and check for companion transmission codes.
- Inspect the sensor connector and wiring for a short-to-ground, corrosion, or damage; repair as needed.
- Test the fluid pressure sensor/switch 'F' and replace it if it reads out of range.
- If fluid, wiring, and sensor are good, have the TCM evaluated. Clear and re-test.
FAQ
Quick answers
Is it safe to drive with P0994?+
Short trips are usually fine, but a genuine low-pressure condition can damage the transmission. Confirm fluid level and repair soon.
Can I just clear P0994?+
It will return once the TCM re-reads a low signal, so fix the fluid, wiring, or sensor rather than only clearing it.
Related codes
Often seen with P0994
Read & clear P0994 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