The drive switch input reports to the engine or gearbox module that range D is selected, usually through its own contact in the range switch or selector next to the park/neutral contact. No maker documents these codes; GM's tables up to 2025, Ford's summaries and Saab service data were searched. The description follows California's rule for inputs, circuit and plausibility checks, and the documented park/neutral input, which is checked against the gearbox module's range. P0855 means the D signal stays at a high level: an open wire with the pull-up lifting the input, a short to voltage or a contact that no longer closes.
Medium severity. Can I keep driving?Drive gently to a repair shop. If it slips, you hear clunks, or it loses its gears, do not keep driving.
Symptoms
- Fault stored, MIL depending on maker
- Gear indicator wrong
- Cruise control not working
Most likely causes
- Signal or ground wire open
- Contact worn or misadjusted, does not close
- Short to voltage
What to check, in order
Start with the simplest. You can tick off each step.
Good to know
- Repair difficulty: medium
- It can trigger limp mode.
What each character of P0855 means
- P: Powertrain: engine and transmission
- 0: Generic code: same on every make
- 8: Transmission
- 55: Specific fault in that system
Frequently asked questions
Can I keep driving with code P0855?
Drive gently to a repair shop. If it slips, you hear clunks, or it loses its gears, do not keep driving.
What causes code P0855?
The most common causes are: signal or ground wire open; contact worn or misadjusted, does not close; short to voltage.
Related codes
- P0853Drive Switch Input Circuit
- P0854Drive Switch Input Circuit Low
- P0852Park/Neutral Switch Input Circuit High
- P0705Transmission Range Sensor A Circuit (PRNDL Input)
Sources
Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.