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DTC codes / P00xx · Fuel and air metering and auxiliary emission controls / P0067

P0067Air Assisted Injector Control Circuit High

P0067 indicates that the powertrain control module (PCM) has detected an abnormally high voltage on the control circuit for an air-assisted fuel injector, which uses compressed air to improve fuel atomization. The PCM expects the circuit to pull the voltage low when activated, but instead it sees voltage at or near battery positive, suggesting an open circuit, a short to power, or a failed injector driver.

SystemPowertrain
Code typeGeneric (all makes)
SeverityMedium
Fix difficultyIntermediate
AreaFuel and air metering and auxiliary emission controls

Symptoms you may notice

  • Illuminated check engine light, often with no other noticeable symptoms
  • Rough idle or misfire under light load, especially when the engine is cold
  • Hesitation or stumble during acceleration
  • Decreased fuel economy
  • Failed emissions test due to increased hydrocarbon emissions
  • In rare cases, the engine may enter limp mode or stall

Common causes, most likely first

  1. Open or damaged wire in the air-assisted injector control circuit
  2. Corroded or loose electrical connector at the injector or PCM
  3. Shorted air-assisted injector solenoid winding
  4. Faulty air-assisted injector driver inside the PCM
  5. Poor ground connection for the injector circuit
  6. Aftermarket alarm or remote start wiring interfering with the circuit
  7. Internal short in the injector due to contamination or wear

How to diagnose and fix it

  1. Verify the code with a scan tool and check for any related pending or history codes
  2. Inspect the air-assisted injector connectors and wiring for damage, corrosion, or loose pins
  3. Measure resistance across the air-assisted injector solenoid and compare to the manufacturer's specification
  4. Check for short to power or open circuit in the control wire between the injector and PCM using a multimeter
  5. Test the injector driver output from the PCM with a noid light or oscilloscope
  6. Repair or replace any damaged wiring or connectors as needed
  7. If all wiring and the injector test good, replace the PCM and reprogram it if required

Don't overlook air pump and injector driver faults

  • A failing secondary air injection pump can cause low air pressure to the injectors, leading to a high voltage code on the control circuit even when the electrical circuit itself is intact.
  • The air-assisted injector driver inside the PCM is a common failure point on higher-mileage vehicles, and it can be misdiagnosed as a bad injector because the injector coil may test good.
  • Corrosion inside the injector connector is frequently missed during visual inspection, so always back-probe the circuit while wiggling the harness to catch intermittent opens.
  • This code can be set by a weak battery or charging system issue that causes the PCM to see erratic voltage spikes on the control circuit, so always check battery health first.
  • Aftermarket electrical accessories tapped into the injector wiring can introduce voltage spikes that trigger P0067, so inspect for non-factory wiring before condemning the PCM.

Can I keep driving with P0067?

You can usually drive the vehicle with P0067, but avoid heavy acceleration and towing until the fault is repaired because the engine may misfire or enter limp mode under load. Prolonged driving with a misfire can damage the catalytic converter, so schedule diagnosis soon.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

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