Air Assisted Injector Control Circuit High
P0067 indicates the air-assisted fuel injector control circuit is reading a voltage signal higher than the ECM expects. This code typically appears on vehicles with air-assisted injection systems where compressed air helps atomize fuel for better distribution across cylinders. The ECM has detected an out-of-range high voltage condition in this circuit.
What You Might Notice
- Hard starting when engine is cold
- Engine smoking or excessive exhaust smoke
- Poor cold start performance
- Engine misfiring or hesitation
- Reduced fuel economy
Most Common Causes
- 1
Damaged Wiring Harness
Broken, pinched, or corroded wiring in the air-assisted injector control circuit can cause incorrect voltage readings. Check for physical damage, corrosion, or loose connectors in the wiring between the ECM and injector.
- 2
Faulty Air-Assisted Injector
A defective injector with an internal short or resistance problem can send abnormally high voltage signals to the ECM. The injector solenoid or control coil may be failing.
- 3
ECM Control Module Issue
A malfunctioning engine control module may misinterpret normal voltage signals or have a faulty input circuit. ECM reprogramming or replacement may be necessary.
- 4
Vacuum Leak in Injector System
A vacuum leak near the air-assisted injector or its associated lines can disrupt normal operation and cause circuit voltage irregularities. This affects the injector's ability to function correctly.
How to Diagnose It
- 1
Check Damaged Wiring Harness — Broken, pinched, or corroded wiring in the air-assisted injector control circuit can cause incorrect voltage readings. Check for physical damage, corrosion, or loose connectors in the wiring between the ECM and injector.
- 2
Check Faulty Air-Assisted Injector — A defective injector with an internal short or resistance problem can send abnormally high voltage signals to the ECM. The injector solenoid or control coil may be failing.
- 3
Check ECM Control Module Issue — A malfunctioning engine control module may misinterpret normal voltage signals or have a faulty input circuit. ECM reprogramming or replacement may be necessary.
- 4
Check Vacuum Leak in Injector System — A vacuum leak near the air-assisted injector or its associated lines can disrupt normal operation and cause circuit voltage irregularities. This affects the injector's ability to function correctly.
How to Fix It
- 1
Inspect and Repair Wiring
Visually inspect the air-assisted injector control circuit wiring for damage, corrosion, or loose connections. Repair or replace damaged wiring harnesses and ensure all connectors are clean and fully seated.
- 2
Test and Replace Air-Assisted Injector
Use a multimeter to test the injector's resistance and continuity. If readings are out of specification or the injector shows signs of failure, replace it with a new or remanufactured unit.
- 3
Check for Vacuum Leaks
Perform a smoke test or visual inspection to locate vacuum leaks around the air-assisted injector, intake manifold, and associated hoses. Repair or replace any damaged vacuum lines.
- 4
Diagnose or Replace ECM
If wiring and injector tests pass, the ECM itself may be faulty. Have the module tested professionally or reprogrammed. In some cases, replacement may be required.
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