P0067

Universal

Air Assisted Injector Control Circuit or Circuit High

Definition source: General OBD-II reference catalog

Definition verification: Not independently verified for display.

Time: Varies by diagnosis and vehicle | Diagnostic difficulty: Medium

Medium Severity

On vehicles equipped with an air-assisted injector system, this code indicates that the control circuit has been detected as high or otherwise outside its expected condition. The system uses air to help disperse fuel from an injector. The code identifies a detected circuit condition; it does not by itself prove that an injector or other part has failed. Exact system design and applicability depend on the vehicle, year, and engine.

Report an error with this code

⚠️ Before You Begin (Safety First)

If the engine runs very roughly, loses power, stalls, or the check-engine light flashes, avoid driving and arrange a safe inspection; continued operation with a severe misfire can cause further damage. If the vehicle runs normally, arrange diagnosis soon and follow the owner's manual.

Common Symptoms

The check-engine light may be on, while the vehicle otherwise appears to run normally.
Rough idle or uneven running may occur if the detected circuit fault affects air-assisted fuel delivery.
Hesitation, reduced power, or poor acceleration may occur if the system's operation is disrupted.
Hard starting or a misfire may occur in some vehicles, but these symptoms are not specific to this code.
There may be no noticeable symptoms if the fault is intermittent or the system's effect on engine operation is limited.

Common Causes

Damaged wiring or a connector problem affecting the air-assisted injector control circuit.
A short to voltage, an open circuit, or another circuit fault that causes the monitored condition to read high; the exact meaning depends on the vehicle's circuit design.
A fault in a control device or related circuit component.
A fault in the air-assist actuator or associated hardware, if fitted and controlled by this circuit.
An intermittent connection or an issue in another part of the system that requires vehicle-specific testing to distinguish.

Diagnostic Steps

Check the owner's manual and vehicle-specific service information to confirm that the vehicle has an air-assisted injector system and that this code applies to its engine.
Record any other diagnostic codes and available freeze-frame information before clearing codes; these can help show when the fault occurred.
With the engine off, visually inspect accessible wiring and connectors related to the system for obvious damage, corrosion, loose connections, or signs of rubbing. Do not disconnect components while the engine is running.
If no obvious issue is found, avoid replacing parts based on the code alone. Have the circuit tested using vehicle-specific information, especially if symptoms are severe or the fault returns.

When to Call a Professional

A technician can use vehicle-specific wiring information and scan data to compare the system's commanded operation with the circuit response. Appropriate checks may include inspecting connectors and wiring, testing for an unintended voltage or an open circuit where relevant, and evaluating the control device and air-assist hardware according to the vehicle's service information. The code alone is not a reason to replace an injector.

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Commonly Asked Questions

Does P0067 prove that an injector needs replacement?

No. It identifies a detected high condition in the air-assisted injector control circuit. Wiring, connections, control components, or other system faults may be involved, so testing is needed before replacing parts.

What does “circuit high” mean?

The monitored circuit was detected at a higher electrical condition than expected for the vehicle's system. The precise interpretation and test method depend on the circuit design; it does not, by itself, identify the failed part.

Can I drive with P0067?

If the vehicle runs normally, arrange diagnosis soon and watch for changes. Stop driving if it stalls, loses substantial power, runs very roughly, or has a flashing check-engine light.

Why might there be no symptoms?

The fault may be intermittent, or the system may have limited effect on how the engine runs under current conditions. The check-engine light can be the only noticeable sign.

Browse Available Code Guides

Previous and next available guides in database record order, across makes. Adjacent entries may share a code number and do not necessarily describe related faults.