Voltage on the 4WD range signal line is above the expected window. Wiring faults of this kind typically come from chafing, water ingress at connector seals, or pin push-back — a wiggle test on the harness while the code is active often confirms the location.
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.
Most likely causes
- Signal wire shorted to B+
- Open sensor element
- Connector pins corroded - high contact resistance
What to check, in order
Start with the simplest. You can tick off each step.
Good to know
- Repair difficulty: medium
What each character of P27A0 means
- P: Powertrain: engine and transmission
- 2: Generic code: same on every make
- 7: Transmission
- A0: Specific fault in that system
Frequently asked questions
Can I keep driving with code P27A0?
Drive gently to a repair shop. If it slips, you hear clunks, or it loses its gears, do not keep driving.
What causes code P27A0?
The most common causes are: signal wire shorted to B+; open sensor element; connector pins corroded - high contact resistance.
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.