P26ADEngine Coolant Bypass Valve B Control Circuit Low
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- How the car detects it
- P26AD indicates a drive line of valve B pulled to ground. GM uses the code differently from the title: on the second-generation Volt (2016 table, VICM) the single coolant bypass valve has an H-bridge motor with two drive lines, and P26AD stands for driver 2 reporting a short to low while the valve is commanded toward the high position. Four failures in five samples at 100 ms set it as Type B; it is one of the codes that blocks P26A5, P26A9 and P15C5. Ford's 2014 gasoline list and its 2020–2025 summaries do not use P26AD. CARB requires output circuit faults to be detected but does not demand separate codes for each fault type. Expect a chafed wire to ground or a shorted motor winding.
- What you may notice
- Check engine light after two drives (GM)
- Valve no longer moves, heating or warm-up affected
- Likely causes
- LikelyDrive wire chafed and shorted to ground
- PossibleShorted valve motor winding
- RareCoolant or water in the connector creating a leak path
- 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: €80 – €700
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.