P26C6 reports that the drive circuit of exhaust valve A sits at too low a voltage – typically because the wiring or the actuator has shorted to ground. Ford's 2024 OBD summary shows that the PCM handles it as failure type 11 of the valve A circuit check, which runs continuously and needs about five seconds; the gasoline summaries 2020–2024 carry a typo here and print P25C6 instead of P26C6 in the threshold table. Deutz lists the same code for its MD1 engines as a low voltage or short on the exhaust flap. Ford bulletin 22-2153 for the Mustang names P26C6 alongside other flap codes and a lit MIL, caused by an exhaust that was not seated correctly. With the circuit pulled low the flap can no longer be commanded; the sister codes P26C5 (open) and P26C7 (high) separate the other fault patterns.
Medium severity. Can I keep driving?You can usually keep driving in the short term. If you smell exhaust fumes in the cabin, stop driving and ventilate the car.
Symptoms
- Check engine lamp on
- Exhaust mode cannot be changed
- Flap stuck in one position, exhaust permanently quiet or loud
Most likely causes
- Control wire chafed through against the body or exhaust and shorted to ground
- Internal short in the flap actuator
- Water or road salt in the actuator connector
What to check, in order
Start with the simplest. You can tick off each step.
Good to know
- Repair difficulty: medium
- It affects emissions.
What each character of P26C6 means
- P: Powertrain: engine and transmission
- 2: Generic code: same on every make
- 6: Control modules and outputs
- C6: Specific fault in that system
Frequently asked questions
Can I keep driving with code P26C6?
You can usually keep driving in the short term. If you smell exhaust fumes in the cabin, stop driving and ventilate the car.
What causes code P26C6?
The most common causes are: control wire chafed through against the body or exhaust and shorted to ground; internal short in the flap actuator; water or road salt in the actuator connector.
Related codes
- P26C5Exhaust Flow Control Valve A Control Circuit/Open
- P26C7Exhaust Flow Control Valve A Control Circuit High
- P2BF9Exhaust Flow Control Valve B Control Circuit Low
- P26FEExhaust Flow Control Valve A Control Performance
Sources
- fordservicecontent.com: OBDSM2400OUTPUT 16Jul2024 WSM final V2 MCS7001
- fordservicecontent.com: OBD Operations Summary Gasoline 2020 2023
- static.nhtsa.gov: MC 10211711 0001
- serdia.deutz.com: DTCList MD1 DE EN
Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.