Fuel and air

P0067 — Air Assisted Injector Control Circuit High

Severity: medium Drive with care, to a shop

What P0067 means

The engine control module monitors the voltage in the control circuit of the air assisted injector, which uses air to help atomize fuel, especially on a cold engine. P0067 sets when that voltage is higher than expected. Typical reasons are a short to voltage, an open circuit, a poor connection or a failing driver inside the module.

Symptoms

  • Check engine light on
  • Hard starting when the engine is cold
  • Rough idle or misfire after a cold start
  • Poor fuel economy
  • Reduced engine performance

Possible causes

  1. Damaged injector wiring: short to voltage, open circuit or high resistance
  2. Corroded or loose electrical connector
  3. Faulty air assisted injector or its solenoid
  4. Failed injector driver inside the PCM/ECM
  5. Vacuum or intake leak affecting the air assist system (less likely)

How to diagnose

  1. Read all codes and freeze frame data, noting whether the fault occurs cold or warm
  2. Inspect the injector harness and connector for chafing, heat damage, corrosion and a loose fit
  3. Measure the solenoid winding resistance and compare it with the specification
  4. Test the control wire for a short to voltage or an open circuit back to the module
  5. Check power and ground at the injector with a meter or scope while the engine runs
  6. Review fuel trims and compare cylinder balance
  7. Check fuel pressure and look for intake or exhaust leaks
  8. If wiring and injector test good, evaluate the PCM driver circuit

Common fixes

  • Repair or replace damaged wiring and connectors
  • Replace the air assisted injector or its solenoid
  • Reprogram or replace the PCM/ECM if the driver fault is confirmed
  • Fix any air leaks, then clear the code and retest

Questions and answers

Can I drive with code P0067?

Usually yes for a short time, but the car may start poorly when cold, run roughly and use more fuel. Get it diagnosed soon to avoid further trouble.

What most often causes P0067?

Wiring and connector problems are the most common: a short to voltage, an open circuit or corroded terminals. After that come the injector and solenoid, and less often the control module.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.