Technical Description of OBD-II Trouble Code
High Circuit Control of Air Assisted Injector
What does that signify?
This diagnostic trouble code (DTC) is a generic powertrain code that applies to OBD-II equipped vehicles with an air assisted fuel injector. It can be found in various vehicle brands such as Subaru, Jaguar, Chevy, Dodge, VW, Toyota, Honda, etc., but it is more commonly seen in Subaru and Jaguar vehicles. Although it is a generic code, the specific repair steps may vary depending on the make, model, and engine.
The Air Assisted injector functions similarly to a normal fuel injector. As the name suggests, it uses air to assist in atomizing the fuel during injection. In most cases, this injector is used to aid cold starts. When the engine is cold, it requires a richer air/fuel mixture (more fuel) to start.
The atomization that occurs when air is introduced to a normal injector is desired because it helps achieve a more evenly distributed spray. This is important because these systems typically use only one injector mounted to the throttle body or intake, and the atomized fuel spray is distributed among multiple cylinders.
The ECM (engine control module) triggers the check engine light with the code P0067 and associated codes when it detects a condition outside the specified range within the Air Assisted Injector’s circuit. Generally, this is an electrical issue, but sometimes an internal malfunction within the injector itself can cause this condition.
The P0067 Air Assisted Injector Control Circuit High code is set when the ECM detects one or more high electrical values within the circuit. This air assisted injector control DTC is closely related to codes P0065 and P0066.
What is the severity of this DTC?
I would classify the severity of this code as moderate to low. This is because it does not significantly affect the overall performance of the engine at normal operating temperature. However, it should be addressed eventually, as consistent cold starts with a potentially lean mixture could cause serious damage in the long run.
What are some of the symptoms of the code?
Symptoms of a P0067 engine code may include:
What are some of the common causes of the code?
Possible causes for this code may include:
What are some troubleshooting steps?
Make sure to check for any technical service bulletins (TSBs) related to your vehicle. Accessing a known fix can save time and money during the diagnosis process.
Tools
When working with electrical systems, it is recommended to have the following basic tools:
Safety Tips
Basic Step #1
Refer to your service manual to locate the injector on your specific make and model. In most cases, the injector is mounted to the throttle body. Check for any vacuum leaks or damaged gaskets around the injector, as these can cause it to operate outside the desired range. Pay special attention to any abnormal whistle noises around the vacuum hoses while the engine is running, as this indicates a leak. If you know how to use a vacuum gauge, monitor the vacuum within the intake system while the engine is running and compare it to the desired value for your vehicle.
NOTE: Replace any cracked vacuum hoses to prevent future issues.
Basic Step #2
Test the injector. The desired electrical values for the injector vary depending on the make and model. Refer to your service manual for the specifications. This will likely involve using a multimeter to measure the resistance between the electrical pins on the injector.
NOTE: Always use appropriate multimeter lead connectors when testing pins/connectors to avoid bending pins and causing intermittent problems.
Basic Tip #3
Inspect the electrical connector on the injector for any corrosion or defects. Repair or replace it as necessary. Since the injector is located in tight areas, check the harness and wires for any chafing. Ensure that the harness and wires are in good condition and properly secured.
NOTE: Disconnect the battery before performing any electrical repairs.
Basic Step #4
Test the injector circuit. If possible, disconnect the connector on the injector and the other end at the ECM. Check for continuity in the wires within the circuit using a multimeter. You can also perform a voltage drop test to assess the integrity of the wire.
Basic Step #5
If your scan tool allows it, monitor the operation of the Air Assisted injector while the vehicle is running. Compare the actual values to the specific desired values to help determine the issue.
