P26A9Engine Coolant Bypass Valve A Position Sensor Stop/Minimum Stop Performance
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Needs a drive cycle to confirm a fix
- How the car detects it
- The title refers to the learned end stop of valve A. GM's use of P26A9 shifted over time. On the 2011 Volt it covered feedback sitting in a forbidden zone (5–30 % or 70–95 %), sudden jumps above 6 % and slow drift above 3 %, all Type B. In the 2016 Volt table the VICM uses it when the valve misses its commanded position within 15 s, retries the end-position learn up to three times with 10 s each, and still fails; coolant must be above 58 °C, and GM notes that an open drive circuit also spoils the learn. The 2016 ELR section treats a failed end-position learn above 50 °C the same way. Subaru's 09-80-21 includes the P26A series. A sticking valve, deposits in the housing or a valve fitted without a relearn are typical causes.
- What you may notice
- Check engine light after two drives
- Engine overheats or stays too cool depending on stuck position
- Weak or uneven cabin heat
- Likely causes
- LikelyValve rotor sticking from deposits or contaminated coolant
- PossibleEnd position not relearned after valve or module replacement
- PossibleOpen motor drive circuit preventing the learn routine
- RareDrifting position sensor misreporting the stop
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €0 – €900
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.