C0309 code meaning
Outlet Valve Rear Right Performance
What C0309 means
C0309 is no part of any public J2012 table, and no manufacturer documents it as a valve code. GM does use it: it is among the keywords of PIP5094, and the GM code chart on AA1Car calls it Motor A/B Circuit High, a transfer case shift motor fault next to C0308 and C0310; that meaning rests on this single source. The title instead names the rear right outlet valve. It opens to let fluid out of the right rear caliper into the accumulator when that wheel tends to lock and stays shut otherwise. Saab's 9-5 checks each valve with a 20 ms pulse at every ignition-on, and a fault turns ABS, traction and stability control off. A valve stuck open would keep the right rear wheel from building pressure.
C0309 at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modePossible
- Repair difficultyHard
- Typical labor1 to 3 hours
- Clears after repairWhen cleared with a scanner
Symptoms of C0309
- ABS and stability control warning lamps on
- Weak braking at the right rear wheel
Common causes of C0309
- PossibleRear right outlet valve not closing fully
- PossibleValve coil or brake module driver faulty
- Less likelyOn GM 4WD trucks, transfer case motor circuit shorted to voltage (GM meaning of the number)
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
ABS solenoid valve rrABS hydraulic blockABS control module
What each part of C0309 means
| C | Chassis system: brakes, ABS, steering and suspension. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 09 | The exact fault in that area. |
What to do next
- Note C0309 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 C0309
What does C0309 mean?
C0309 means "Outlet Valve Rear Right Performance". C0309 is no part of any public J2012 table, and no manufacturer documents it as a valve code. It is a generic code, so it means the same on every make.
Is it safe to drive with C0309?
Drive gently and only to a workshop. With C0309 the car can go into limp mode (reduced power) to protect itself.
Will C0309 fail an emissions test?
C0309 is not an emissions code, so on its own it usually does not fail an emissions test. Other stored codes or a lit check engine light still can.
How hard is C0309 to fix?
Difficulty: hard. A typical repair takes 1 to 3 hours of work. This is a job for a workshop.
Will C0309 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.