P278B
Kick Down Switch Circuit Range/Performance
The kick-down switch state is implausible against accelerator pedal position. 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.
- Check engine light: Yes
- Emissions related: No
- Repair difficulty: easy
Common causes
Ordered by how often each turns out to be the cause.
- Switch trip point driftPossible
- Accelerator pedal travel out of specPossible
- Sensor element aged beyond calibration windowLess likely
Parts involved
- Kickdown Switch
- Accelerator Pedal
P278B is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.