Fault Family System: Powertrain (P-Codes) 5 SAE Codes

Kickdown Switch Circuit

Diagnostic & Technical Explanation

Code P278A (Kick Down Switch Circuit) sets when the TCM sees an open, shorted, implausible, or intermittent signal from the kick-down switch at the accelerator pedal's full-travel stop, used to force a downshift for maximum acceleration. Causes are a worn switch plunger no longer reaching its contact point, a corroded connector under the pedal assembly, or chafed wiring in the driver footwell harness.

These 5 diagnostic trouble codes share one detection mechanism and one repair path, which is why MechanicDB groups them into a single authored fault family rather than repeating the same explanation 5 times.

Codes in this family (5)

Code	Definition	Repair coverage
P278A	Kick Down Switch Circuit	3 ranked fixes
P278B	Kick Down Switch Circuit Range/Performance	3 ranked fixes
P278C	Kick Down Switch Circuit Low	3 ranked fixes
P278D	Kick Down Switch Circuit High	3 ranked fixes
P278E	Kick Down Switch Circuit Intermittent/Erratic	3 ranked fixes

What this page does not show

This page publishes the fault mechanism and the code index. The licensed dataset adds, for every one of the 15,886 codes, the full authored repair set (56,729 procedures in total) with the fields deliberately withheld here:

Procedures 2..n after the first-listed procedure
Aftermarket parts cost ranges in USD (est_parts_cost_min/max_usd)
Professional labor-hour estimates (est_labor_hours)
Step-by-step diagnostic and repair instructions
Replacement-part mappings and catalog lookups
6,637 manufacturer-specific OEM codes across 32 makes ($149 tier)

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