P278A
Kick Down Switch Circuit
The kick-down switch (under the accelerator pedal at full travel) circuit is faulty. The transmission cannot detect the driver's full-throttle downshift request.
- Check engine light: Yes
- Emissions related: No
- Repair difficulty: easy
Common causes
Ordered by how often each turns out to be the cause.
- Switch contacts worn or corrodedCommon
- Broken wire to switchPossible
Parts involved
- Kickdown Switch
- Accelerator Pedal
- Wiring Harness
P278A 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.