P278E Kick Down Switch Circuit Intermittent/Erratic

P278E stands for a kickdown switch signal that drops out or toggles irregularly. No manufacturer documents P278E publicly; the monitoring idea follows CARB's call for circuit checks on inputs, and Eaton's Endurant HD diagnostics show the networked equivalent, where a kickdown message that is invalid or absent for 5 s is logged as fault 167. Intermittent faults at the pedal usually come from a contact that bounces as the detent wears, a connector that loosens with pedal vibration, or a harness that flexes with every pedal stroke until a strand breaks. Because the fault is not permanent, a scan with the car at rest often finds nothing. The driver feels kickdown working on one occasion and not on the next.

Likely causes

Symptoms

• Kickdown works only sometimes
• Fault not reproducible when stationary

Repair estimate

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

Related codes

References: law.cornell.edu, productinfo.serviceranger4.com.