The P0066 code indicates that the engine control module has detected a voltage signal below the normal operating range in the air-assisted injector control circuit. This typically suggests an electrical fault, such as a short to ground or an open circuit, within the actuator or its associated wiring.
An internal electrical failure or short within the actuator itself is the most common cause.
Frayed, rubbed, or broken wires causing a short to ground or an open circuit.
Moisture or debris in the electrical connectors leading to high resistance or poor connectivity.
A blown fuse in the circuit providing power to the air-assisted injector system.
An internal failure in the PCM's driver circuit for the air-assisted injector.
It uses compressed air to help atomize fuel more effectively in the combustion chamber, which reduces emissions and improves efficiency in certain diesel engines.
Depending on the manufacturer, it may limit engine power to protect components or reduce emissions violations.
No. It is very rare for the PCM to fail in this specific circuit. Most cases are caused by actuator failure or wiring damage; replacing the PCM without first verifying the wiring is typically incorrect.