OBD-II code · Powertrain (generic, extended)
P278D Kick Down Switch Circuit High
Voltage on the kick-down switch 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.
Is it safe to drive with P278D?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyOpen switch contacts
- PossibleSwitch wire shorted to B+
- Less likelyConnector pins corroded - high contact resistance
Repair at a glance
- Difficulty
- Easy
- DIY friendly
- Often, with basic tools
- Typical labour
- 0.3–1.5 h
- Emissions test
- Usually unaffected
- Parts involved
- Kickdown Switch, Wiring Harness
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.