Fault Family System: Powertrain (P-Codes) 15 SAE Codes

Shift Switch Circuit

Diagnostic & Technical Explanation

Code P0815 (Upshift Switch Circuit) sets when the TCM sees an open, shorted, or implausible signal from the driver's up/down manual-shift switch (steering column or paddle), or a mismatch against the transmission range signal. Causes are worn switch contacts, a damaged clockspring connection, or chafed wiring at the column/paddle assembly.

These 15 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 15 times.

Codes in this family (15)

Code	Definition	Repair coverage
P0815	Upshift Switch Circuit	3 ranked fixes
P0816	Downshift Switch Circuit	3 ranked fixes
P0819	Up and Down Shift Switch to Transmission Range Correlation	3 ranked fixes
P0826	Up and Down Shift Switch Circuit	3 ranked fixes
P0827	Up and Down Shift Switch Circuit Low	3 ranked fixes
P0828	Up and Down Shift Switch Circuit High	3 ranked fixes
P085F	Up and Down Shift Switch Circuit Range/Performance	3 ranked fixes
P2775	Upshift Switch Circuit Range/Performance	3 ranked fixes
P2776	Upshift Switch Circuit Low	3 ranked fixes
P2777	Upshift Switch Circuit High	3 ranked fixes
P2778	Upshift Switch Circuit Intermittent/Erratic	3 ranked fixes
P2779	Downshift Switch Circuit Range/Performance	3 ranked fixes
P2780	Downshift Switch Circuit Low	3 ranked fixes
P2781	Downshift Switch Circuit High	3 ranked fixes
P2782	Downshift 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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