P0067 – Meaning, Symptoms, Causes & How to Fix It

P0067 is an OBD-II trouble code you’ll usually see on vehicles that use an intake air assist or auxiliary air injection system, often on some Subaru, VW/Audi, and a few other makes. It points to an electrical issue in the “air assisted injector control circuit high,” which means the ECU is seeing more voltage than it expects. While this code doesn’t usually mean your engine is about to fail, it can affect drivability, fuel economy, and emissions. With a basic scan tool and some patience, you can often narrow it down quickly.

What Does P0067 Mean?

P0067 stands for “Air Assisted Injector Control Circuit High.” In plain English, your engine computer (ECU) has detected an abnormally high voltage signal in the circuit that controls an air-assist valve or solenoid used to help atomize fuel, especially during cold starts and light load conditions.

This system uses an electrically controlled valve or solenoid to add extra air near the injectors or intake ports. When the circuit voltage is higher than the ECU’s expected range, it flags P0067. The problem can be in the solenoid, wiring, connectors, or sometimes inside the ECU itself.

Quick Reference

Code: P0067
Definition: Air Assisted Injector Control Circuit High
Severity: Low to moderate – usually safe to drive short term
Common Symptoms: Rough cold start, poor idle, possible check engine light only
Typical Causes: Faulty air-assist solenoid, wiring short to power, connector corrosion

Real-World Example / Field Notes

In the shop, I most often see P0067 on Subarus with air-assist injectors. A common scenario: the car comes in with a check engine light, maybe a slightly rough cold start, but drives fine once warm. After pulling the code, I’ll check freeze-frame data and find it set during a cold start. A quick inspection usually reveals a damaged harness near the intake manifold or a corroded connector at the air-assist solenoid. Once the wiring is repaired and the connector cleaned or replaced, the code stays gone and cold starts smooth out.

Symptoms of P0067

Check engine light on: The MIL/SES light will usually be the first and most obvious sign.
Rough cold start: The engine may stumble, hesitate, or feel weak right after starting, especially in cold weather.
Unstable idle: You might notice a slightly rough idle or small RPM fluctuations when the engine is cold.
Reduced fuel economy: Poor fuel atomization can cause increased fuel consumption in city driving.
Higher emissions: You may fail an emissions test or inspection due to the stored code and mixture issues.
Occasional hesitation: Light throttle or low-speed hesitation can appear when the system is trying to use air assist.
No noticeable drivability change: In some cases, the only symptom is the stored code and warning light.

Common Causes of P0067

Most Common Causes

Faulty air-assist solenoid/valve: The solenoid coil can short internally, causing higher than normal voltage or current draw.
Short to power in wiring: The control wire from the ECU to the solenoid can rub through and contact a 12V source, driving the circuit voltage too high.
Corroded or damaged connector: Moisture intrusion at the solenoid or harness connector can create poor contact and incorrect voltage readings.
Previous wiring repairs: Poorly done splices or aftermarket modifications near the intake or injector harness can alter circuit resistance and voltage.

Less Common Causes

ECU internal fault: A failing driver circuit inside the engine control unit can misread or overdrive the air-assist circuit.
Ground issues: High resistance or broken grounds shared by the solenoid and other components can skew voltage readings.
Aftermarket accessories: Add-on remote starters, alarms, or performance modules tied into injector or intake wiring can interfere with the circuit.
Rodent damage: Chewed wires around the intake manifold area can cause intermittent shorts or opens in the control circuit.

Diagnosis: Step-by-Step Guide

You’ll want a basic OBD-II scan tool (preferably one that can read live data and Mode $06), a digital multimeter, and access to a wiring diagram for your specific vehicle. A test light and some contact cleaner also come in handy. Always start with a visual inspection before diving into deeper electrical testing.

Confirm the code and check freeze-frame data. Use your scan tool to verify P0067 is present and note engine temperature, RPM, and conditions when it set. This helps you duplicate the problem.
Inspect the air-assist solenoid and wiring. Locate the air-assisted injector valve/solenoid (often near the intake manifold). Look for cracked insulation, rubbed-through wires, or loose and corroded connectors.
Check for other related codes. See if there are injector, O2 sensor, or other air/fuel related codes. Multiple codes can point to a shared power or ground issue.
Test solenoid resistance. With the connector unplugged and key off, measure resistance across the solenoid terminals. Compare to spec from a service manual. A shorted or open coil indicates a bad solenoid.
Check for short to power. With the solenoid disconnected, turn the ignition ON and use a multimeter to check the control wire for unexpected battery voltage. If you see constant 12V where there shouldn’t be, you have a short to power in the harness.
Verify power and ground supply. Confirm the solenoid is getting proper power and ground when commanded by the ECU. Use a wiring diagram to identify which pin is which and test with a multimeter or test light.
Command the solenoid with a scan tool (if supported). Some scan tools allow you to activate the air-assist solenoid. Listen and feel for a click and watch voltage changes. No response may indicate a bad solenoid or ECU driver.
Wiggle test the harness. While monitoring the live data or voltage on the circuit, gently move the wiring harness. If the reading spikes or drops, you’ve likely found a broken or shorted wire.
Inspect ECU connectors. If everything else checks out, inspect the ECU plugs for bent pins, corrosion, or water intrusion. This is less common but worth verifying.
Clear the code and road test. After repairs, clear P0067 and perform a cold start and short drive cycle. Re-scan to confirm the code does not return.

Pro tip: Use Mode $06 data (if your scan tool supports it) to check for pending or borderline test results related to the air-assist or injector circuits. This can show you if the system is close to failing again before the light comes back on.

Possible Fixes & Repair Costs

Most repairs for P0067 are straightforward once you pinpoint the fault. Common fixes include replacing the air-assist solenoid/valve, repairing or replacing damaged wiring, cleaning or replacing corroded connectors, or in rare cases, replacing the ECU. At a typical independent shop, you might spend around $100–$200 for wiring and connector repairs, $150–$350 for solenoid replacement, and $500–$1,200+ if an ECU is required. Costs vary by vehicle make, labor rates, parts availability, and how difficult the solenoid or harness is to access.

Can I Still Drive With P0067?

In most cases, you can still drive with P0067 without immediate danger to the engine. The car may start a bit rough when cold and might use a little more fuel, but it usually runs normally once warmed up. That said, you should avoid long-term driving with any active check engine light. If you notice severe rough running, stalling, or other codes appearing, park the vehicle and get it checked as soon as possible.

What Happens If You Ignore P0067?

Ignoring P0067 for a long time can lead to increased fuel consumption, higher emissions, and potential damage to the catalytic converter from poor mixture during cold starts. It can also cause you to fail an emissions or inspection test and make it harder to spot new issues because the check engine light is already on.

Last updated: February 13, 2026

Key Takeaways

P0067 means the ECU detects a high voltage issue in the air assisted injector control circuit.
Symptoms are usually mild: check engine light, rough cold start, and slightly rough idle.
Most common causes are a bad air-assist solenoid, wiring shorts, or connector corrosion.
Diagnosis focuses on visual inspection, resistance testing, and checking for shorts to power.
Repairs are often affordable unless an ECU is required; address it promptly to avoid emissions issues.

Vehicles Commonly Affected by P0067

P0067 tends to show up more often on vehicles that use air-assisted injectors or auxiliary air systems for cold start emissions control. You’ll commonly see it on Subaru models (Impreza, Forester, Outback), some Volkswagen and Audi vehicles, and certain Asian imports that use similar air-assist systems. It can appear on both gasoline sedans and small SUVs, especially those from the early to mid-2000s through the mid-2010s. However, any OBD-II equipped vehicle with an air-assisted injector circuit can potentially store this code.

FAQ

Can P0067 cause serious engine damage?

Usually no. P0067 by itself typically does not cause immediate engine damage. It can, however, lead to poor cold start mixture and higher emissions. Over a long period, that can stress the catalytic converter, so you still want to fix it sooner rather than later.

Is P0067 hard to diagnose at home?

It’s manageable if you’re comfortable with basic electrical testing. With a wiring diagram, multimeter, and a decent scan tool, you can often track it down. The biggest challenge is usually accessing the solenoid and harness, not the actual testing.

Can I clear P0067 and keep driving if it doesn’t come back?

You can clear the code once and monitor it. If P0067 doesn’t return after several cold starts and drive cycles, it may have been an intermittent or one-time glitch. If it comes back, you should proceed with a proper diagnosis instead of repeatedly clearing it.

Does P0067 mean I need new fuel injectors?

Not usually. P0067 points to the air-assisted injector control circuit, not the injectors themselves. The issue is more often the air-assist solenoid, wiring, or connector. Injectors are only replaced if separate tests show they’re faulty.

Can a bad battery or alternator trigger P0067?

A weak battery or charging system problem can cause voltage fluctuations that confuse the ECU, but they’re not the most common cause of P0067. Still, if you’re experiencing other electrical issues or low voltage codes, it’s smart to test the battery and alternator as part of your diagnosis.

P0067 – Air Assisted Injector Circuit High