Fault Family System: Powertrain (P-Codes) 12 SAE Codes

Exhaust Flow Control Valve

Diagnostic & Technical Explanation

Code P26C5 (Exhaust Flow Control Valve A Control Circuit/Open) sets when the ECM detects an open circuit, a short to ground or voltage, or a performance deviation while driving exhaust flow control valve A, the butterfly valve in the exhaust used to raise backpressure for faster catalyst warm-up, quiet operation, or exhaust tuning. Causes are a valve shaft seized by exhaust carbon and corrosion, a failed actuator motor exposed to underbody spray, or damaged control wiring along the exhaust routing.

These 12 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 12 times.

Codes in this family (12)

Code	Definition	Repair coverage
P26C5	Exhaust Flow Control Valve A Control Circuit/Open	3 ranked fixes
P26C6	Exhaust Flow Control Valve A Control Circuit Low	3 ranked fixes
P26C7	Exhaust Flow Control Valve A Control Circuit High	3 ranked fixes
P26FE	Exhaust Flow Control Valve A Control Performance	3 ranked fixes
P2BF8	Exhaust Flow Control Valve B Control Circuit/Open	3 ranked fixes
P2BF9	Exhaust Flow Control Valve B Control Circuit Low	3 ranked fixes
P2BFA	Exhaust Flow Control Valve B Control Circuit High	3 ranked fixes
P2BFB	Exhaust Flow Control Valve B Control Performance	3 ranked fixes
P2D13	Exhaust Flow Control Valve C Control Circuit/Open	3 ranked fixes
P2D14	Exhaust Flow Control Valve C Control Circuit Low	3 ranked fixes
P2D15	Exhaust Flow Control Valve C Control Circuit High	3 ranked fixes
P2D16	Exhaust Flow Control Valve C Control Performance	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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