P27CF code meaning
Pressure Control Solenoid R Control Circuit Low
Powertrain system Generic code P27xx codes Check engine light
What P27CF means
P27CF tells that the control line of solenoid R is held low, as if shorted to ground. On the Corvette dual-clutch transmission GM (23OBDG07, still present in 24OBDG07) monitors synchronizer actuation valve 4 while energized; the driver chip compares the sense pin with a threshold of roughly 1.7 V and, after 150 ms below it, reports a ground fault rated Type A. Ford's TR9070 list gives P27CF to a shorted switch on SPV4. A ground short bypasses the driver, so the valve can apply rods 3 and 4 towards A when no shift is wanted; the controller then usually locks the affected gears. Chafed insulation, a crushed harness clip or a coil shorted to its housing are typical finds.
P27CF at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyMedium
- Typical labor1 to 4 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P27CF
- MIL on
- Unwanted rod movement, gears locked out
- Limp mode
Common causes of P27CF
- Most likelyChafed insulation grounding the control line
- PossibleHarness crushed at a clip or bracket
- Less likelySolenoid R coil shorted to its housing
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Pressure control solenoid rWiring harness
What each part of P27CF means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| 7 | Area: transmission. |
| CF | The exact fault in that area. |
What to do next
- Note P27CF 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 P27CF
What does P27CF mean?
P27CF means "Pressure Control Solenoid R Control Circuit Low". P27CF tells that the control line of solenoid R is held low, as if shorted to ground. It is a generic code, so it means the same on every make.
Is it safe to drive with P27CF?
Drive gently and only to a workshop. With P27CF the car can go into limp mode (reduced power) to protect itself.
Will P27CF fail an emissions test?
Yes, it can. P27CF 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 P27CF to fix?
Difficulty: medium. A typical repair takes 1 to 4 hours of work. This is a job for a workshop.
Will P27CF clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.