P2681
Engine Coolant Bypass Valve A Control Circuit / Open
The controller cannot drive the engine coolant bypass valve A. The valve usually routes coolant around the radiator during warm-up; without it warm-up takes longer and emissions during the warm-up phase rise.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: medium
Common causes
Ordered by how often each turns out to be the cause.
- Open coil in bypass valve solenoidCommon
- Broken control wirePossible
Parts involved
- Coolant Bypass Valve A
- Solenoid
- Wiring Harness
P2681 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.