Damaged, chafed or shorted wiring in the air assist control circuit, such as a short to voltage; Corroded, loose or contaminated connector terminals at the air assist actuator, solenoid or control unit; Faulty air assist solenoid, valve or actuator with an internal electrical fault; Fault in the shared power supply or earth feeding the air assist circuit, such as a blown fuse or poor earth; Internal driver fault in the engine control unit; Outdated control unit software where the manufacturer has a documented fix for this fault.

P0067

Air Assisted Injector Control Circuit High.

Generic
Powertrain
Generic code
Medium severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
0: AreaFuel and air metering, auxiliary emission controls
67: FaultThe specific fault in that area

What it means

P0067 is the generic code for a high condition in the air assisted injector control circuit. The engine control unit monitors the circuit that drives the air assist function on the injectors, and it has seen a voltage or signal level higher than expected for the commanded state. Air assisted injection is only used on a small number of engines, so the exact layout depends on the make and model.

Symptoms

Malfunction indicator lamp on
Rough idle or unstable idle speed
Hesitation or poor throttle response
Poor cold starting or extended cranking
Increased fuel consumption
Higher exhaust smoke or a noticeable fuel smell

Possible causes

Damaged, chafed or shorted wiring in the air assist control circuit, such as a short to voltagelikely
Corroded, loose or contaminated connector terminals at the air assist actuator, solenoid or control unitlikely
Faulty air assist solenoid, valve or actuator with an internal electrical faultpossible
Fault in the shared power supply or earth feeding the air assist circuit, such as a blown fuse or poor earthpossible
Internal driver fault in the engine control unitrare
Outdated control unit software where the manufacturer has a documented fix for this faultrare

How to diagnose

Read all stored and pending codes and note the freeze frame data, including engine temperature, load and speed at the time the code set.
Check for other related codes, especially other injector, fuel trim or air assist codes, as they can point to a shared cause.
Look up the air assist system layout for the specific model and engine, as the components and circuit differ between applications.
Visually inspect the wiring harness and connectors for chafing, heat damage, water ingress, corrosion and bent or pushed-back pins.
Check the relevant fuses, relay and the power and earth supplies to the air assist circuit against the wiring diagram.
Measure the circuit voltage at the actuator connector with the ignition on and when commanded, and compare it with the manufacturer's specification.
Test the resistance of the air assist solenoid or actuator against the specified value, and check the wiring for a short to voltage.
Check for a manufacturer software update or technical bulletin relating to this code before condemning the control unit.

How to fix

Repair or replace damaged wiring and fix any short to voltage in the circuit.
Clean, repair or replace corroded or damaged connectors and terminals.
Replace the air assist solenoid, valve or actuator if it fails electrical tests.
Restore the correct power and earth supply, replacing any faulty fuse or relay and fixing the cause of the failure.
Update the control unit software if an outdated calibration is confirmed as a known cause, and repair or replace the control unit only if testing proves an internal fault.

Can I keep driving?

Medium severity

The car can usually be driven for a short time, but fix it soon as poor running and extra fuel use may get worse. Avoid long journeys or heavy loads if the engine runs roughly or hesitates.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.