The P0065 code indicates that the Powertrain Control Module (PCM) has detected a range or performance problem in the air injection system, specifically the air assisted injector control circuit. This system uses an air pump and solenoid to inject air into the fuel stream for improved atomization and reduced emissions. The code sets when the PCM sees an unexpected voltage or resistance in the control circuit.
The solenoid itself may be stuck, have an internal open or short, or fail to operate within the expected range, directly causing the circuit performance issue.
Chafed, broken, or shorted wires in the solenoid control circuit can cause incorrect voltage readings. Look for damage near the solenoid, along the harness, or at the PCM connector.
Corrosion, bent pins, or a loose connector at the air assisted injector solenoid can create high resistance or intermittent contact, triggering the code.
A clogged air filter, kinked hose, or failed air pump (if separate) can alter the expected performance of the air injection system, leading to a range/performance fault.
A rare cause; the PCM may have an internal fault in the driver circuit for the air assisted injector. This should only be considered after all other possibilities are ruled out.
It is a system that injects a small amount of air into the fuel spray near the intake valve, improving fuel atomization for better combustion and lower emissions, especially during cold starts.
Driving with this code is usually possible, but you may experience reduced performance, poor fuel economy, or stalling. Prolonged driving could lead to catalytic converter damage if the air-fuel mixture is incorrect.
No, PCM failure is very rare for this code. Many drivers are incorrectly told to replace the PCM, but the problem is almost always a faulty solenoid, wiring issue, or air supply problem. A thorough diagnosis of the simpler components should always come first.
Diagnosis involves checking the air assisted injector solenoid's resistance, inspecting the wiring and connectors for damage, verifying power and ground, and testing the control circuit. A professional scan tool can also command the solenoid to confirm operation.