P21D7Cylinder 9 Injector B Circuit/Open
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- How the car detects it
- P21D7 would mark an open drive circuit of the second injector on cylinder 9, which presupposes at least nine cylinders. No manufacturer documents this code publicly; the published Ford and GM lists stop at cylinder 8 (P21D6). Engines with that many cylinders and two injection systems do exist, for example the V10 of the Lamborghini Huracán, which pairs direct with multipoint injection, but no source shows how its maker labels the two injectors. CARB requires that electrical output components such as fuel injectors be checked for circuit faults, so the logic would follow the documented siblings: a missing current or excessive impedance when the injector is switched. The direct injector of cylinder 9 would carry P0209 if it is the A side. A misfire on cylinder 9 (P0309) is the likely accompanying symptom.
- What you may notice
- Check engine light on
- Misfire on cylinder 9 (P0309)
- Likely causes
- LikelyOpen coil in the second injector of cylinder 9
- PossibleBroken wire or terminal in the injector harness
- RareDriver stage in the engine control module failed
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Hard · Usually a job for a workshop.Typical cost: €150 – €1,000
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.