P0272 - CYLINDER 4 CONTRIBUTION / BALANCE

Fuel injectors play an important role in vehicle performance and efficiency. They provide the cylinders with the necessary amount of air/fuel mixture.

Vehicle manufacturers have incorporated an injector into each cylinder. However, in some cases, operation relies on a single fuel injector for all cylinders. These injectors have an internal electromagnet that is actuated to open and close the fuel passage.

P0272 OBD2 fault code will be set if the Powertrain Control Module (PCM) determines that there is an erratic operation of the injector on cylinder 4.

• Check Engine light illuminated.
• Engine knocking.
• Difficulty accelerating the vehicle.
• Fuel consumption increases.

The reasons for the DTC P0272 OBDII code being set are:

• The fuel injector may be blocked.
• The wiring related to the injector may be faulty.
• The fuel injector connector on cylinder 4 is possibly bad.
• The fuel injector may be faulty.

To troubleshoot the P0272 OBD2 diagnostic code you should consider the following:

• Consult the TBS (Technical Service Bulletins) related to the year and make of the vehicle. In these, you will find useful information for diagnosis.
• Check if the wiring harness and injector connector of cylinder 4 is in good condition. If obvious defects are found, repair or replace them as necessary.
• With a voltmeter, check the injector circuit voltage. If you find a lack of current, it is due to an open circuit. Repair it as appropriate.
• Check the cylinder injector and verify that it is not clogged. If it is clogged, you should clean it and proceed to clear the code.
• If after performing all of the above checks the P0272 OBDII code is still set, replace the cylinder 4 injector.
• Start the engine and let it run until the fuel pressure drops and it stops.
• Clamp the fuel return line with a needle vise.
• Remove the crusher valve from the fuel pump inspection port on the fuel rail. Install the hose into the test port.
• Screw a can of injector cleaner onto the hose and wait a few seconds until the cleaner pressurizes the fuel rail. Start the engine and run the vacuum cleaner until it stops.
• Remove the purifier hose from the test port and reinstall the Schrader valve. Remove the clamps from the return line vise and install the fuel pump fuse.
• Erase the DTC and reset the PCM with a conventional code reader.
• Start the engine. If it continues to idle and the code returns, replace the fuel injector.