Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Exhaust Flow Control Valve - Exhaust Tuning
Exhaust flow control valves are used to control exhaust acoustics under differing vehicle operating conditions. The valve controls the exhaust flow through two flow paths within the muffler. The normal de-energized/open valve state results in normal tuned exhaust sound while the energized/closed valve provides an alternate path through the muffler with additional sound dampening. The 2016 MY Mustang GT350 and Focus RS use a PWM (pulsewidth modulated) signal to control the exhaust valve position. Dual bank exhaust systems have two valves (one per bank) controlled by a single PCM output.
The actuator consists of electric motor, worm gear, position sensor and electronic control unit all integrated into a housing.
The Exhaust Flow Control Valve has no position feedback and limited component diagnostic capability. The valve can pull the PWM line down to indicate that the exhaust valve is stuck.
| DTCs | P26C5: Exhaust Flow Control Valve "A" Control Circuit/Open P26C6: Exhaust Flow Control Valve "A" Control Circuit Low P26C7: Exhaust Flow Control Valve "A" Control Circuit High P26FE: Exhaust Flow Control Valve "A" Control Performance |
| Monitor Execution | Continuous |
| Monitor Sequence | None |
| Sensors OK | Not Applicable |
| Monitoring Duration | 5 seconds |
| P26C5, P25C6, P25C7 - Smart driver reports output circuit fault P26FE - Exhaust Flow Control Valve reports stuck valve (via PWM line) |
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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