P0067 — Air Assisted Injector Circuit High #

Note: The description for code P0067 may vary depending on the vehicle manufacturer. Always refer to your OEM (Original Equipment Manufacturer) service information for precise definitions.

• Air Assisted Injector Circuit High (General, most brands)
• Air Injection System High Voltage (Toyota/Lexus)
• Air Assisted Injector Control Circuit High Input (Ford, some Mazda)
• Air Injector Circuit Voltage High (Honda/Acura)

Summary of Code P0067 #

P0067 is an OBD-II (On-Board Diagnostics, generation 2) trouble code that relates to the air assisted injector control circuit. This system is used in select engines to inject additional air into the intake stream, primarily to improve emissions, especially during cold starts. When your engine control module (ECM) detects an abnormally high voltage in the air assisted injector circuit, it triggers this code. While P0067 is not as common as other injector-related codes, it can be a sign of an electrical fault, wiring issue, or a failed component. Left unaddressed, it may affect engine performance and emissions compliance.

Frequent Symptoms for Code P0067 #

Drivers may notice a combination of performance and emissions-related symptoms when this code is active. In many cases, the check engine light illuminates with little to no noticeable change in driveability, but sometimes there are clear signs.

• Check Engine Light (CEL) illuminated
• Rough idle on cold start
• Poor fuel economy
• Difficulty passing emissions tests
• Possible slight hesitation or stumble when accelerating from a cold start
• No noticeable symptoms in some cases

Probable Causes for Code P0067 #

The most common causes of P0067 are related to the electrical circuit of the air assisted injector. Problems may range from simple wiring faults to component failure. Below are the likely causes, listed in order of frequency:

1. Open or short to power in the air assisted injector wiring harness
2. Faulty air assisted injector solenoid or valve
3. Poor electrical connection or corroded connector pins
4. Faulty Engine Control Module (rare)

Step-by-Step Diagnostic for Code P0067 #

Diagnosing P0067 requires a logical approach, ideally with a digital multimeter and access to the vehicle’s wiring diagrams. Here’s a recommended step-by-step process:

• Verify the code with a scan tool and note any freeze frame data (when the code was set).
• Visually inspect the air assisted injector’s wiring harness for damage, chafing, or corrosion.
• Disconnect the air assisted injector and inspect both the connector and pins for moisture, dirt, or corrosion.
• Check for continuity and resistance in the injector circuit using a multimeter, comparing to OEM specifications.
• Test for excessive voltage at the connector with the key on (reference service manual for expected voltage).
• Command the injector on/off with a scan tool if possible, monitoring circuit response.
• If all wiring and connections check out, test or replace the air assisted injector solenoid/valve.
• As a last resort, consider ECM testing or replacement, but only after ruling out all other possibilities.

Possible Repairs for Code P0067 #

Once the root cause is identified, repairs should directly address the specific issue found. Here are the most common solutions, matched to their causes:

• Repair or replace damaged wiring in the air assisted injector circuit
• Clean and secure electrical connectors; replace if corrosion is present
• Replace the air assisted injector solenoid or valve if faulty
• Update or reprogram the ECM (rare, only if confirmed defective)

Can You Drive with Code P0067? #

Limited. While many vehicles with P0067 can be driven without immediate risk of breakdown, you may experience increased emissions and rough running during cold starts. It is not recommended to ignore this code, especially if local emissions laws apply. For best engine performance and to avoid potential long-term damage, have the issue inspected and repaired promptly.

Vehicles Most Commonly Affected by P0067 #

While P0067 is relatively rare, it tends to appear in certain makes and models that utilize air assisted injector systems. These include:

• Toyota (Camry, Corolla, Prius, RAV4)
• Honda (Civic, Accord, CR-V)
• Ford (Focus, Escape, Fusion)
• Lexus (ES, RX series)
• Mazda (select models)

Common Mistakes & Best Practices for P0067 #

Misdiagnosis of this code often leads to unnecessary parts replacement or incomplete repairs. Avoid these common pitfalls:

• Replacing the air assisted injector without first checking wiring and connectors
• Ignoring intermittent faults caused by loose or corroded pins
• Overlooking related codes that could indicate a shared ground or power issue
• Neglecting to use OEM wiring diagrams for accurate troubleshooting
• For best results, always clear the code after repairs and verify the fix with a road test

Quick FAQ for P0067 #

Is P0067 likely to damage my engine if I keep driving?
No, immediate engine damage is unlikely, but poor running and increased emissions can occur, especially during cold starts. Prolonged neglect may affect other emissions components.

Can I fix P0067 myself?
If you are comfortable with basic electrical testing and have access to a multimeter, you may be able to locate and repair simple wiring or connector issues. For solenoid or ECM replacement, professional assistance is recommended.