Skip the auto shop - Our mechanics make house calls
  1. Home
  2. Articles
  3. P0279 OBD-II Trouble Code: Cylinder 7 Injector Circuit Low

P0279 OBD-II Trouble Code: Cylinder 7 Injector Circuit Low

check engine light

P0279 code definition

Code P0279 is stored by the PCM when it experiences a low-voltage situation that involves the fuel injector for the number seven cylinder.

What the P0279 code means

Basically, this code means that one of your vehicle’s fuel injectors is failing, which could be happening for a number of reasons. Every make and model has a voltage spectrum that is considered acceptable by the manufacturer’s predetermined standards. Voltage variations that exceed 10% of this acceptable range will cause the code to be stored. Usually, a Check Engine light comes on too.

What causes the P0279 code?

Many things could cause a voltage issue with the number seven fuel injector. The most common reason would be that the wiring has been damaged by wildlife. Squirrels and other creatures can sense the warmth from your engine after it’s been in use and will climb up under your hood and snuggle up to it. Unfortunately, many won’t be satisfied with the extra warmth and will actually chew through wires.

Other causes include:

  • A clogged fuel injector
  • A defective fuel injector
  • Loose connector faces
  • Loose electrical wiring
  • Corroded electrical features
  • A bad fuel injector driver within the PCM

What are the symptoms of the P0279 code?

When a fuel injector isn’t working properly, you should expect a lack of power coming from the engine. It will most likely run a lot rougher too. Your fuel economy should take a hit as well. On most vehicles, you’ll also see the Check Engine light come on, though it might take a few failed cycles before this happens.

How does a mechanic diagnose the P0279 code?

A qualified mechanic will begin by using a scanner to diagnose what codes are affecting your vehicle and then use a noid lamp, ohmmeter and the service manual to get a better idea of the issue behind P0279, specifically. Then they’ll move onto doing a visual examination of all connectors and wires. Usually, this is all that is necessary, but in some cases, the fuses may need to be checked on too. After each inspection, the code should be cleared and the system retested before moving on.

Common mistakes when diagnosing the P0279 code

PCM failure could be a reason for the P0279 code, but it’s incredibly unlikely. Before the PCM is ever replaced, every other possibility should be exhausted. A lot of times, it’s just open or shorted circuits inhibiting the defective fuel injectors or fuel injection system that make it seem as though the PCM isn’t working correctly.

How serious is the P0279 code?

The P0279 is not one you want to be driving around with. Having it fixed should definitely be an immediate priority. Any time one of your fuel injectors isn’t working correctly, you run the risk of all kinds of other problems occurring – some of which could be very expensive to repair. Fuel injectors are central to your vehicle’s operation, so if one doesn’t work correctly, it causes a ripple effect. The PCM will even change up how your engine works to accommodate the missing signals from fuel injector number seven.

What repairs can fix the P0279 code?

To repair the problems related to P0279 code, your mechanic will likely do one of the following:

  • Clean a dirty injector
  • Replace a bad injector
  • Replace or tighten the injector’s electrical connector

The majority of the time, your mechanic will do the last one on this list. Corroded or simply loose connectors keep the injector from receiving sufficient voltage.

Additional comments for consideration regarding the P0279 code

It’s pretty hard to misdiagnose this one, but some have accidentally blamed the PCM because they didn’t inspect the fuel injectors well enough. This is a costly mistake.

Need help with a P0279 code?

YourMechanic has certified mobile mechanics who will visit you at your home or office to assess your vehicle and perform any necessary repairs. You can fill out an online form or give us a call at 1-800-701-6230 to schedule your appointment with one of our service advisors and receive a free quote.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
Icon-warranty_badge-02

Skip the repair shop, our top-rated mechanics come to you.

At your home or office

Choose from 600+ repair, maintenance & diagnostic services. Our top-rated mechanics bring all parts & tools to your location.

Fair & transparent pricing

See labor & parts costs upfront, so you can book with confidence.

12-month, 12,000-mile warranty

Our services are backed by a 12-month, 12,000-mile warranty for your peace of mind.

Get A Quote

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.

GET A QUOTE

More related articles

P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the...
Veteran and Military Driver Laws and Benefits in New Mexico
The state of New Mexico offers a number of benefits and perks for those Americans who have either served in an Armed Forces branch...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...


Related questions

Q: Does the VIN number have to be in the ECM for the vehicle to run?

Some new ECMs will give you a certain amount of free starts before it will not start unless the VIN is added. I am not sure if this is the case with your ECM but you have a dealer telling...

Q: SES light crack noise

Hello. The symptoms you describe are actually a common known occurrence among 135i models. The 135i uses a turbocharged engine that generates high boost pressures, which can sometimes cause boost hoses to come free due to excessive pressure. I would...

Q: Would the throttle positioning sensor cause the engine to rev up while driving?

Your issues may stem from a variety of components. Have the vehicle scanned for diagnostic troubleshooting codes. This will give you more information on any issues the computer has detected. Some will not illuminate the Check Engine Light. The vehicle...