P278E: Kick Down Switch Circuit Intermittent/Erratic
What to do
Drive normally — but do not plan an overtake around the kick down until it is repaired. Flooring the pedal may not deliver the immediate downshift you expect, so allow more room than usual. If you need stronger acceleration in the meantime, select a lower gear manually before committing rather than relying on the pedal.
What this code means
The kick down switch signal is cutting in and out.
An intermittent signal is a connection fault until proven otherwise. A switch that has failed outright reads failed all day; a signal that comes and goes moves with vibration, temperature and steering angle — which points at a connector, a chafed run of harness, or a clock spring part-way through failing.
Kick down is the floor-it request. Push the accelerator through the last of its travel and the transmission drops a gear or two at once for maximum acceleration — the overtaking reflex. On older automatics the request comes from a physical switch under the pedal's full travel; on newer cars it is a firm detent at the end of the pedal sensor's range that behaves as one. This circuit is that switch.
The car drives normally without it. Gears still change on schedule and the throttle still works. What is lost is the emergency reflex: flooring the pedal produces strong acceleration in the current gear rather than the immediate downshift you were counting on. The difference only shows at the moment you need it most, which is what makes an unrepaired kick down circuit worth more respect than its symptoms suggest.
Check the simple things before the expensive ones. A floor mat riding up under the pedal, a switch knocked out of adjustment, a connector disturbed by footwell work — the kick down switch lives in one of the harshest, most trodden corners of the car, and it corrodes and shifts like anything else that lives there.
Likely causes
Start here
- Faulty kick down switch · moderate
- Corroded or loose connector · specialist
Less common
- Damaged wiring harness · specialist
Rare
- Faulty transmission control module · specialist
Symptoms
Components involved
Information, not instruction
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Community experience
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