P0271 OBD-II Trouble Code: Cylinder 4 Injector Circuit High

P0271 code definition

Cylinder 4 Injector Circuit High

What the P0271 code means

This diagnostic trouble code (DTC) indicates that a reference voltage from the fuel injector associated with cylinder number 4 has gone higher than the range of acceptance set by the vehicle manufacturer. The powertrain control module (PCM) realizes this and will store a trouble code.

What are the causes of the P0271 code?

• The fuel injector associated with cylinder number 4 is restricted causing a pressure spike and therefore a higher reference voltage.

• The wiring or connector associated with the fuel injector on the number 4 cylinder may be damaged in some way.

• The powertrain control module could be malfunctioning.

What are the symptoms of the P0271 code?

• A rough idling condition will likely be present.
• The engine may hesitate or stumble during acceleration.
• A misfire condition will likely exist.
• A Check Engine Light may be illuminated.

How does a mechanic diagnose the P0271 code?

• A mechanic may diagnose this trouble code by first checking the fuel injector on the number 4 cylinder for proper function using the manufacturer’s suggested procedure.

• Next, the mechanic would ensure the integrity of the wiring and connector associated with the fuel injector on cylinder number 4.

If everything checks out during these two tests:

• The mechanic may run a fuel system cleaning through the engine to try to break any restrictions that may exist down inside the fuel injector.

• If all else fails, the likelihood of the powertrain control module being faulty is high and it would therefore be tested and replaced as necessary.

Common mistakes when diagnosing the P0271 code

An engine diagram is essential for diagnosing this issue due to the fact that it is easy to test the wrong fuel injector without it. Testing the wrong fuel injector would be a major mistake as it would certainly lead to a misdiagnosis and potentially hours of wasted time.

How serious is the P0271 code?

Any trouble code that can cause a misfire condition would be considered very serious and should be taken care of very soon. Misfires can cause damage to the engine and certain components of the exhaust system. Ensure that all repairs are done by a qualified professional as this repair relates to the fuel system.

What repairs can fix the P0271 code?

• Repairing or replacing wiring or connectors that are associated with the fuel injector on the number 4 cylinder

• Replacing the fuel injector that is associated with the number 4 cylinder

• Running a fuel system cleaning through the engine to release any restriction

• Replacing the powertrain control module

Additional comments regarding the P0271 code

Using quality fuel in your vehicle can help to prevent the restrictions that can build up inside the fuel injectors. Bad quality fuel can gunk up inside the fuel rail and cause multiple problems such as misfires and even a no start condition. Never use old or contaminated fuel in your vehicle.

Need help with a P0271 code?

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