P088D code meaning
Reverse Inhibit Control Circuit High
What P088D means
The reverse inhibit solenoid on GM's six-speed manual gearboxes (Corvette, Camaro, CTS-V, ATS-V) blocks reverse while driving forward and is released by the engine module. A low-side driver with built-in diagnosis watches the control line: above 9 V and 250 rpm, 20 faults in 25 samples of 250 ms (about 6 s) set the code. GM rates it type C without MIL; from 2019 a service message appears. P0801 is the open circuit. P088D means the control line is shorted to voltage: when the driver switches on it sees too high a level or overcurrent, and the solenoid can no longer be operated, so reverse may stay locked.
P088D at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modeNot expected
- Repair difficultyMedium, DIY possible
- Typical labor0.5 to 2.5 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P088D
- Reverse cannot be engaged (lockout not released) or is not blocked
- Service message (GM from 2019), no MIL
Common causes of P088D
- Most likelyControl wire shorted to a supply wire in the harness
- PossibleSolenoid coil low-resistance or shorted (driver overcurrent)
- PossibleMoisture or corrosion between supply and control pin
- Less likelyEngine module driver faulty
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Reverse lockout solenoidSolenoid wiringEngine control moduleManual transmission
What each part of P088D means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 8 | Area: transmission. |
| 8D | The exact fault in that area. |
What to do next
- Note P088D 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 P088D
What does P088D mean?
P088D means "Reverse Inhibit Control Circuit High". The reverse inhibit solenoid on GM's six-speed manual gearboxes (Corvette, Camaro, CTS-V, ATS-V) blocks reverse while driving forward and is released by the engine module. It is a generic code, so it means the same on every make.
Is it safe to drive with P088D?
P088D does not normally turn on the check engine light by itself. Watch for the symptoms above and have it checked soon.
Will P088D fail an emissions test?
P088D 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 P088D to fix?
Difficulty: medium. A typical repair takes 0.5 to 2.5 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will P088D clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.