P0277 OBD-II Trouble Code: Cylinder 6 Injector Circuit High

P0277 code definition

This code means that there is an injector circuit malfunction affecting cylinder six.

What the P0277 code means

When this code appears, the ECM (engine control module) has reported that either the resistance of voltage for the fuel injector circuit for cylinder six is out of specification.

What causes the P0277 code?

There are four main reasons P0277 may be displayed:

• A faulty electrical connection
• The cylinder six injector has either failed or is failing
• The ECM could simply be faulty
• Electrical connections could not be working correctly

What are the symptoms of the P0277 code?

There are a number of symptoms you’ll want to look out for that are all signs of the underlying problem causing the P0277 code. The first is the ECM illuminating the Check Engine light. The ECM may also enact failsafe mode. It’s doing this because the P0277 code represents an issue that could actually damage your vehicle from within. Failsafe mode will remain on until the circuit’s performance is restored to within the acceptable limits or the fault is simply repaired.

If your engine is running poorly, that could also be a symptom. Unfortunately, this symptom may give way to a much more serious one: your engine completely dying. After that, it may refuse to restart. Even if it doesn’t die, you may find it very difficult to get the engine to start. Misfiring is also a common symptom. You may also notice that your vehicle simply isn’t getting the fuel efficiency you’re used to.

How does a mechanic diagnose the P0277 code?

To diagnose the problem, most mechanics will follow some version of the following:

• Use a scan tool to check for all codes currently showing for your vehicle
• Check freeze frame data for a list of all the codes that were found
• Clear the codes and take the vehicle out for a test drive under conditions similar to the freeze frame data that triggered the P0277 code
• Inspect all of cylinder six injector circuit’s components
• Check for voltage at the fuel injector
• Use the scan tool to examine injector six voltage and resistance and then compare it to other injectors
• Install a noid light between the wiring harness and fuel injector cylinder six to assess pulse width
• Test the ECM

Common mistakes when diagnosing the P0277 code

More often than not, the fuel injector is behind the P0277 code. This is especially true on high mileage vehicles and is why it’s so important to comprehensively test it. Otherwise, the mechanic may move on and make a miscellaneous diagnosis of the problem.

How serious is the P0277 code?

You need to be careful about driving a vehicle that is displaying the P0277 code. If one of the symptoms you’re experiencing is the engine running poorly, you really shouldn’t drive it at all. Instead, get it looked at by a professional ASAP.

What repairs can fix the P0277 code?

• Repair or replace the wiring harness
• Fix connection issues
• Replace the fuel injector cylinder six
• Replace the ECM

Additional comments for consideration regarding the P0277 code

The higher the mileage is on your vehicle, the more likely that contamination has built up during this time. As time goes on, the likelihood of seeing P0277 increases. To help combat this, clean out your fuel system.

Mechanics may use all kinds of specialty tools to diagnose P0277. One example would be a noid light set. This is an effective and quick way to check the pulse width. They can also test the fuel injector.

A grade scan tool will most likely be used as well. Professional-level scanners list all codes present, but also make it easy to check for injectors and sensors operating properly.

Need help with a P0277 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.