P0799

Pressure Control Solenoid C Intermittent

Transmission Generic OBD-II Medium

What it means

P0799 means the transmission control module detected an intermittent fault in the pressure control solenoid C circuit, which regulates hydraulic line pressure. When the signal drops out, line pressure wavers, so the transmission occasionally slips or shifts harshly rather than failing outright. It won't cause a no-start; the goal is to find the intermittent wiring or solenoid fault before it becomes constant and wears the clutches.

Medium

Can I keep driving? Shifts may occasionally slip or turn harsh as pressure control drops out; drivable for now, but fix it before it becomes constant.

Common symptoms

What you'll notice

Intermittent slipping or improper shifts
Harsh or delayed shifting
Reduced fuel economy
Check-engine light on (may come and go)

Common causes

Most likely first

Intermittent wiring or connector fault in the pressure control solenoid C circuitLikely
Faulty pressure control solenoid CCommon
Low or contaminated transmission fluidCommon
Transmission control module (TCM) faultLess often

How to diagnose & fix

Work through it in order

Read freeze-frame data to capture the conditions when it set.
Wiggle-test the solenoid C wiring and connector to reproduce the fault.
Check transmission fluid level and condition.
Test the pressure control solenoid C resistance and operation.
If wiring and solenoid are good, suspect the TCM. Clear and re-test.

FAQ

Quick answers

Is it safe to drive with P0799?+

Usually yes, short-term. Because the fault is intermittent, you'll see only occasional slipping or harsh shifts. Repeated slipping wears the clutches, so repair it soon.

Can I just clear P0799?+

It will come back when the circuit drops out again. Trace and repair the intermittent wiring, connector, or solenoid causing it.

Read & clear P0799 yourself

Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.

▶ Get it on Google Play

✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX