P0067 — Air Assisted Injector Control Circuit High

P0067 — Air Assisted Injector Control Circuit High. A fault in the fuel delivery and mixture control. Short, gentle driving to a shop is usually possible. Typical causes: faulty fuel rail pressure sensor or wiring, faulty fuel pressure regulator, clogged or leaking fuel injectors.

powertrain (engine/transmission)

Is it safe to drive?

Schedule repair promptly P0067 usually does not require immediate shutdown if the engine runs normally, but rough idle, hesitation, or stalling should prompt reduced driving and prompt diagnosis. Avoid hard acceleration or extended travel until the control circuit is repaired and P0067 remains cleared.

Typical symptoms

The check-engine light may illuminate with P0067 stored in the powertrain control module.
The engine may idle roughly, surge, or sound unstable while the air-assisted injector is not receiving correct electrical control.
Acceleration may show hesitation, stumble, or a brief loss of power.
Cold starting may be difficult, particularly when the air-assisted injection system is most active.
Fuel economy may decrease, and the exhaust may smell rich if the injector is not atomizing fuel as commanded.
Severe electrical faults may cause stalling, although P0067 can also remain present with only mild drivability symptoms.

Common causes

An open or high-resistance section of the air-assisted injector control circuit can leave the PCM seeing excessive voltage and set P0067.
The control wiring may be shorted to battery voltage rather than being pulled to the expected command level.
The air-assisted injector control solenoid or its internal winding may be shorted, open, or overheated.
Corroded, loose, water-damaged, or poorly seated terminals in the injector, solenoid, or PCM connectors can create a high circuit reading.
A failed PCM output driver or internal feedback circuit is possible after wiring and connector faults have been ruled out.

How to diagnose with an OBD scanner

Confirm P0067 and capture operating conditions Connect an OBD scanner, ELM327 adapter, or AIScanAuto, then read stored, pending, and freeze-frame data. Confirm that P0067 is current and note battery voltage, engine speed, coolant temperature, and whether the fault appears during startup or acceleration. A generic scanner may not display the air-assisted injector command or feedback signal.
Inspect the control circuit and connectors With the ignition off, inspect the wiring and electrical connectors for the air-assisted injector, its control solenoid, and the PCM. Look for separated terminals, green corrosion, water intrusion, damaged insulation, pinching, or chafing. Also verify that related connectors are fully seated and that any specified power and ground terminals are clean.
Measure commanded control voltage Back-probe the specified control pin and compare its voltage with the service wiring diagram. On a typical low-side circuit, an active command should pull the circuit close to ground; an open circuit or short to battery voltage can leave it high and trigger P0067. If the vehicle uses a high-side driver, use the diagram's expected values instead.
Separate the component from the harness With the engine off, disconnect only the electrical connector for the air-assisted injector or control solenoid and perform continuity or load testing. Compare readings at the component and PCM sides of the harness. Do not disconnect fuel fittings. A high reading that follows the wiring points away from the component; one that remains with the component isolated suggests a circuit short or module fault.
Repair and verify the fault Repair the open, short, corroded terminal, or failed control component responsible for the high reading. Clear P0067 with the scanner, then operate the engine through a cold start and several load transitions while monitoring for a return code. The repair is not complete unless P0067 does not return and the driveability symptoms have resolved.

Approximate repair cost

Typical independent-shop estimates for diagnosing and repairing P0067 are about USD 150 to $900, depending on whether the result is a wiring or connector repair or replacement of the air-assisted injector or its control solenoid. Figures are estimates and vary by region.

Common questions

Does P0067 mean the air-assisted injector is clogged?

No. P0067 identifies an excessively high voltage in the air-assisted injector control circuit. A restriction or dirty injector may cause separate performance codes, so the electrical circuit should be tested before assuming an internal fuel-delivery failure.

Can I continue driving with P0067?

You can drive cautiously if the engine runs smoothly and there are no warning messages beyond the stored code. Stop driving if P0067 is accompanied by severe misfire, stalling, fuel leakage, or a substantial loss of power.

What is the first test for P0067?

First use an OBD scanner or ELM327/AIScanAuto to confirm the current code and freeze-frame conditions, then inspect the injector-control wiring and connectors. Voltage testing at the control pin determines whether the high reading comes from an open, a short, or the component.

Will clearing P0067 permanently fix the problem?

No. Clearing P0067 only removes the code and freeze-frame information from the controller. The underlying high-voltage fault will set P0067 again unless the wiring, connector, control solenoid, air-assisted injector, or PCM fault is corrected.

When your engine control unit detects a problem with the voltage on the air assisted injector control circuit, it stores trouble code P0067. This code falls within the powertrain category, specifically tied to fuel delivery and mixture regulation. The "circuit high" designation tells you that the module is seeing supply voltage — or something dangerously close to it — on a circuit that should normally carry a much lower, variable signal. That unexpected voltage reading triggers the check engine light and logs the fault for later diagnosis.

The air assisted injection system adds pressurized air directly into the fuel injector stream, improving atomization and combustion efficiency, especially during cold starts and hard accelerations. The powertrain control module continuously monitors the electrical feedback from this circuit. If the signal stays outside its acceptable window for more than a few drive cycles, the ECU locks in P0067 and captures freeze frame data — a snapshot of RPM, engine load, coolant temperature, and vehicle speed at the exact moment the fault occurred. That snapshot is your best clue when you start troubleshooting.

The underlying cause of that high voltage reading usually falls into one of three categories: a wire shorted to a constant power source, a broken ground path preventing the circuit from pulling low, or a failed component that drags the signal up on its own. Once P0067 is active, the engine runs on a less precise fuel map, which is why drivers notice drivability problems almost immediately.

Symptoms of P0067

The check engine light is the first and most obvious sign that P0067 has been stored. Beyond that warning lamp, expect one or more of the following:

Extended cranking time or hard starting, especially when the engine is warm
Rough idle that feels uneven or surging
Hesitation and stumble during acceleration
Noticeably higher fuel consumption compared to normal
Reduced engine power under load, such as climbing hills or passing
A strong fuel odor inside the cabin or near the tailpipe in more severe cases

Common Causes

P0067 rarely appears without a root electrical or mechanical issue behind it. The most frequent culprits include:

A signal wire shorted directly to battery positive voltage
A failed air assisted injector control assembly pulling the circuit high
An open ground return for the air assisted injector circuit
Faulty fuel rail pressure sensor or associated wiring harness damage
Contaminated, diluted, or incorrect fuel in the system
Clogged or leaking fuel injectors disrupting normal delivery
A weak fuel pump or a severely restricted fuel filter starving the rail

How to Diagnose P0067

Effective diagnosis starts with information and works outward to the physical components. Follow these steps in order:

Connect an OBD2 scanner and confirm P0067 is present in the trouble code list. Record the freeze frame data associated with the code — it tells you exactly what the engine was doing when the fault triggered.
Look for any related diagnostic trouble codes stored at the same time. Correlated codes often point directly to the failing part. Check manufacturer TSB databases for known software corrections or warranty extensions tied to this code.
Perform a hands-on inspection of the wiring harness and connectors feeding the air assisted injector and fuel rail pressure sensor. Look for melted insulation, broken terminals, corrosion from moisture intrusion, or connectors that are not fully seated.
With the air assisted injector unplugged, probe the signal circuit at the harness connector. If you still read high voltage with the component disconnected, the harness itself has a short to power. If the voltage drops to normal reference range, the air assisted injector is the likely culprit.
Verify fuel rail pressure at idle and under simulated load using a gauge, then compare results to the manufacturer's specification. Low or unstable pressure suggests a pump, filter, or pressure regulator problem.
Review short-term and long-term fuel trim data on the scanner. Large positive trims indicate the ECU is adding extra fuel because the mixture is running lean — a common pattern when P0067 is active.
Clear the code, complete a drive cycle that reproduces the freeze frame conditions, and verify P0067 does not return.

Repair Options and Costs

Address the cheapest and most common failures before spending money on major components:

Replace the fuel pump — parts and labor typically run $400–$900
Clean or replace fuel injectors — expect to pay $200–$800 depending on whether cleaning is sufficient or new injectors are needed
Replace the fuel pressure regulator or sensor — generally $150–$450
Replace the fuel filter — usually $80–$200

Most shops quote labor separately from parts, so these ranges reflect the full invoice at an independent repair facility. DIY mechanics who source their own parts and perform the work can spend significantly less.

Driving Safety Verdict

P0067 carries a caution severity rating. While the engine may continue running, mixture control faults can produce stalling in traffic, unpredictable hesitation under acceleration, and — if left unresolved — excess fuel washing the catalytic converter and causing costly damage downstream. Do not treat this as a cosmetic issue. Schedule diagnostics promptly and avoid long highway trips until the root cause is identified and corrected.