The powertrain control module (PCM) has detected voltage above the calibrated threshold in the control circuit for the air-assisted injector solenoid valve. This valve regulates supplementary air injection into the intake ports to improve fuel atomization and reduce cold-start emissions. A 'high' reading typically indicates a short to voltage, an open circuit, or an internal fault within the solenoid itself.
The solenoid may have an internal short-to-power or coil resistance that has drifted out of specification, causing the circuit voltage to read higher than expected by the PCM.
The low-side control wire between the PCM and the solenoid has rubbed through or melted against a power feed, causing battery voltage to back-feed into the circuit.
A broken wire, severed trace, or disconnected connector can cause the PCM to see reference voltage (full system voltage) on the feedback line, interpreting it as a 'high' signal.
Green corrosion, bent pins, or moisture intrusion in the valve connector can create high-resistance paths or intermittent opens that trigger the high-voltage fault.
Rarely, the output driver inside the PCM that grounds the solenoid circuit may fail in a way that causes a voltage feedback error, but this should only be considered after the solenoid and wiring are proven sound.
The definition is universal; the diagnostics are engine-specific. Open your vehicle for the codes documented for it:
Generally yes, but fuel economy and emissions will suffer. The condition does not pose an immediate risk of mechanical engine damage, though the vehicle may fail an emissions inspection.
Almost never. Despite being a common recommendation by inexperienced technicians, PCM failure causing this specific code is extremely rare. The root cause is almost always the air-assist solenoid valve or wiring damage. Only consider PCM replacement after exhaustive testing proves the solenoid and entire circuit are functioning correctly.
It refers to a system that injects compressed air into the intake ports along with fuel spray to improve atomization, allowing more complete combustion and reduced emissions during cold starts and low-load conditions.
A 'High' code indicates the PCM sees more voltage than expected on the control line. This is most often caused by the wire shorting to a power source, an open circuit allowing reference voltage to appear un-dropped, or the solenoid internally shorting to its own power feed.