What is the P0067 code?
The diagnostic code P0067 is a generic powertrain code. It indicates an electrical problem in the air assisted injector control circuit. Although it can appear on various brands (Subaru, Jaguar, VW, Toyota, etc.), it is primarily encountered on Subaru and Jaguar vehicles. Repair steps may vary depending on the model.
Function of the Air Assisted Injector
This injector uses air to improve fuel atomization, which is crucial for cold starts. A cold engine requires a richer air/fuel mixture. The introduced air allows for a finer and more uniform spray, optimizing fuel distribution to the cylinders.
Why the Code Illuminates
The Engine Control Module (ECM) detects an abnormally high electrical value in the circuit and triggers the check engine light. This code is often associated with codes P0065 and P0066.
Severity of the P0067 Code
The severity is moderate. The vehicle will operate normally once the engine is warm, but difficult cold starts with a lean mixture can cause long-term damage. Repair is recommended.
Symptoms of the P0067 Code
- Hard starting in cold weather
- Exhaust smoke
- Poor engine performance when cold
- Misfires
- Increased fuel consumption
Possible Causes of the P0067 Code
- Damaged or cut wiring harness
- Vacuum leak at the injector or pipes/clamps
- Faulty fuse or relay
- Faulty air assisted injector
- Problem with the ECM
- Corrosion or overheating of pins/connectors
Tools Needed for Diagnosis
- OBD2 scanner
- Digital multimeter
- Socket and wrench set
- Screwdriver set
- Electrical contact cleaner
- Vehicle repair manual
Safety Instructions
- Let the engine cool down before any work.
- Chock the vehicle’s wheels.
- Wear personal protective equipment (safety glasses, gloves).
- Always disconnect the battery before working on the electrical circuit.
Diagnostic Procedure for Code P0067
Step 1: Checking for Vacuum Leaks
Consult the manual to locate the injector (often on the throttle body). With the engine running, listen for any abnormal hissing indicating an air leak. Visually inspect the intake pipes and seals. Replace any cracked or worn hoses.
Step 2: Injector Test
Using a multimeter, measure the resistance across the injector terminals. Compare the obtained value with that specified in the repair manual. A significant deviation indicates a faulty injector.
Tip: Use appropriate multimeter connectors to avoid damaging fragile pins.
Step 3: Connector and Wiring Inspection
Inspect the electrical connector of the injector for any corrosion, overheating, or damage. Check the condition of the wiring harness along its entire length to identify potential chafing or wear.
Step 4: Electrical Circuit Test
Test the continuity and resistance of the wires between the injector and the ECM. A voltage drop test can also reveal poor circuit integrity.
Step 5: Real-World Condition Test (if possible)
If your scan tool allows it, activate the air assisted injector and monitor its operating values in real-time. Compare them with the target values.
Step 6: Checking Technical Service Bulletins (TSB)
Before replacing parts, consult your vehicle’s Technical Service Bulletins (TSB). The manufacturer may have issued a known fix for this specific problem, saving you time and money.
Conclusion and Call to Action
Diagnosing the P0067 code requires a methodical approach, starting with the simplest checks (leaks, connectors). If the troubleshooting steps above do not resolve the issue, it is highly recommended to consult a professional mechanic with the expertise and diagnostic equipment specific to your vehicle model.