Fault Family System: Powertrain (P-Codes) 4 SAE Codes

Economy Mode Switch Circuit

Diagnostic & Technical Explanation

Code P05C7 (Economy Mode Switch Circuit/Open) sets when the ECM detects an open, shorted, or implausible signal from the driver-selectable economy/eco driving-mode switch. Causes are worn switch contacts, a stuck button, or chafed wiring at the center console/dash switch bank.

These 4 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 4 times.

Codes in this family (4)

Code	Definition	Repair coverage
P05C7	Economy Mode Switch Circuit/Open	3 ranked fixes
P05C8	Economy Mode Switch Circuit Range/Performance	3 ranked fixes
P05C9	Economy Mode Switch Circuit Low	3 ranked fixes
P05CA	Economy Mode Switch Circuit High	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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