P21EDCylinder 9 Injector B Circuit High
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- How the car detects it
- P21ED is defined for a B injector circuit on cylinder 9 that reads high, meaning the control side is shorted to supply or, on some designs, the two injector wires touch. No manufacturer publishes thresholds or vehicles for it. Only engines with ten or more cylinders and dual injection could set it; Lamborghini's Huracán V10 with direct plus multi-point injection is the documented example, although its A/B naming is not public. CARB requires that an output component be flagged when it does not respond properly to commands, which is exactly the case here: the injector cannot be switched, so cylinder 9 depends on its other injector alone. Lean running at loads where both injectors work together is the likely result. Low fault: P21EC; A injector high fault: P0286.
- What you may notice
- Check engine light on
- Cylinder 9 lean in mixed injection operation
- Misfire on cylinder 9 (P0309)
- Likely causes
- LikelyControl wire of the cylinder 9 B injector shorted to power
- PossibleBoth injector wires bridged in the harness
- PossibleInjector coil shorted internally
- RareDriver stage in the control unit faulty
- 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 – €1,200
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.