P21D9
Cylinder 11 Injector B Circuit/Open
The drive circuit of cylinder 11 second injector (B) is open. Modern direct-injection systems sometimes use a port-injection backup; injector B refers to that secondary set.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: hard
Common causes
Ordered by how often each turns out to be the cause.
- Injector winding openCommon
- Pin pushed back out of connector bodyLess likely
- Cracked solder joint inside the module or sensorLess likely
Parts involved
- Fuel Injector
P21D9 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.