P0066Air Assisted Injector Control Circuit Low
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Needs a drive cycle to confirm a fix
- How the car detects it
- Air-assisted injectors have an air sleeve around the nozzle tip: air flowing past at high speed breaks the fuel spray into finer droplets, which improves combustion and cold starts and lowers hydrocarbon emissions. On port-injected engines this air is taken upstream of the throttle and dosed by a pulse-width modulated bypass solenoid; because it bypasses the throttle, it is part of the idle air. The system is rare and mainly found on older engines. P0066 reports too low a voltage in the control circuit of the air-assist solenoid, typically a short to ground or, depending on the circuit, an open circuit.
- What you may notice
- Check engine light on
- Unstable idle
- Poorer cold starting
- Likely causes
- LikelyShort to ground or open circuit in the control or supply wire
- LikelySolenoid coil open or high resistance
- PossibleConnector corroded
- RareOutput driver in the engine control module faulty
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Often possible to do yourself.Typical cost: €40 – €150
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.