OBD-II code · Powertrain (generic, extended)
P21CF Cylinder 1 Injector B Circuit/Open
The drive circuit of cylinder 1 second injector (B) is open. Modern direct-injection systems sometimes use a port-injection backup; injector B refers to that secondary set.
Is it safe to drive with P21CF?
Usually safe for short trips, but don’t ignore it: the underlying fault can get more expensive over time.
Common causes
- Most likelyInjector winding open
- Less likelyPin pushed back out of connector body
- Less likelyCracked solder joint inside the module or sensor
Repair at a glance
- Difficulty
- Hard
- DIY friendly
- Best left to a mechanic
- Typical labour
- 1–4 h
- Emissions test
- Likely to fail
- Parts involved
- Fuel Injector
Related codes
- P21D0Cylinder 2 Injector B Circuit/Open
- P21D1Cylinder 3 Injector B Circuit/Open
- P21D2Cylinder 4 Injector B Circuit/Open
- P21D3Cylinder 5 Injector B Circuit/Open
- P21D4Cylinder 6 Injector B Circuit/Open
- P21D5Cylinder 7 Injector B Circuit/Open
- P21D6Cylinder 8 Injector B Circuit/Open
- P21D7Cylinder 9 Injector B Circuit/Open
- P21D8Cylinder 10 Injector B Circuit/Open
- P21D9Cylinder 11 Injector B Circuit/Open
- P21DACylinder 12 Injector B Circuit/Open
- P21CCReductant Control Module Supply Voltage High
- P21CDReductant Quality Module Supply Voltage Low
- P21CEReductant Quality Module Performance
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.