P0799 code meaning
Pressure Control Solenoid C Intermittent
Powertrain system Generic code P07xx codes Check engine light
What P0799 means
Pressure control solenoids are current-controlled proportional valves, and what B and C mean depends on the design: on GM's clutch-to-clutch automatics they are the pressure valves of clutches 2 and 3, on GM's CVT B is primary pulley pressure and C line pressure, on Jatco CVTs B is the secondary pressure valve, on Saab's AF40 B and C are clutch valves SLC1/SLC2. P0799 is an intermittent electrical fault of valve C. No manufacturer document available to us uses it; Saab's AF40 catches short dropouts within its circuit codes (five times in 100 ms). A loose contact or chafed harness is the likely cause; harsh shifts or limp mode appear at times.
P0799 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyMedium
- Typical labor1 to 4 hours
- Clears after repairAfter a drive cycle
Symptoms of P0799
- Limp mode or harsh shifts at times
- Warning lamp comes and goes
Common causes of P0799
- Most likelyLoose contact or corroded connector
- PossibleChafed harness
- Less likelyCoil with heat-dependent winding fault
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Pressure control solenoidTransmission valve bodyTransmission clutchesTransmission control module
What each part of P0799 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 7 | Area: transmission. |
| 99 | The exact fault in that area. |
What to do next
- Note P0799 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P0799
What does P0799 mean?
P0799 means "Pressure Control Solenoid C Intermittent". Pressure control solenoids are current-controlled proportional valves, and what B and C mean depends on the design: on GM's clutch-to-clutch automatics they are the pressure valves of clutches 2 and 3, on GM's CVT B is primary pulley pressure and C line pressure, on Jatco CVTs B is the secondary pressure valve, on Saab's AF40 B and C are clutch valves SLC1/SLC2. It is a generic code, so it means the same on every make.
Is it safe to drive with P0799?
Drive gently and only to a workshop. With P0799 the car can go into limp mode (reduced power) to protect itself.
Will P0799 fail an emissions test?
Yes, it can. P0799 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P0799 to fix?
Difficulty: medium. A typical repair takes 1 to 4 hours of work. This is a job for a workshop.
Will P0799 clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.