OBD-II code · Powertrain (generic, extended)

P26AC Engine Coolant Bypass Valve B Control Circuit / Open

The controller cannot drive the second coolant bypass valve. The associated cooling sub-loop cannot be regulated.

Is it safe to drive with P26AC?

Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.

Common causes

  • Most likelyOpen coil in bypass valve solenoid
  • PossibleBroken control wire

Repair at a glance

Difficulty
Medium
DIY friendly
Best left to a mechanic
Typical labour
1–3.5 h
Emissions test
Usually unaffected
Parts involved
Coolant Bypass Valve B, Solenoid, Wiring Harness

Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.