P0273 Fault Code

P0273 OBD-II Trouble Code Short Description

Cylinder #5 Injector Circuit Low

What does trouble code P0273 mean?

P0273 is a diagnostic trouble code (DTC) that is specific to the cylinder #5 injector circuit in a vehicle's engine. This code indicates that there is a low voltage condition detected in the injector circuit of the fifth cylinder.

The injector circuit is responsible for delivering fuel to the individual cylinders of the engine. When the engine control module (ECM) determines that there is a low voltage condition in the circuit, it triggers the P0273 code and illuminates the check engine light.

There are several potential causes for a low voltage condition in the injector circuit:

  1. Faulty injector: The injector itself may be malfunctioning, resulting in a low voltage condition. This could be due to internal wiring issues or a defective solenoid.
  2. Poor electrical connection: Loose or corroded electrical connections can lead to insufficient voltage reaching the injector. This can be caused by damaged wiring or connectors.
  3. Faulty engine control module: In some cases, the ECM itself may be faulty and not providing the correct voltage to the injector circuit.

To diagnose and repair the P0273 code, the following steps can be taken:

  1. Scan the vehicle's ECM: A professional diagnostic scanner can be used to retrieve the specific fault code and identify any other related codes.
  2. Inspect the injector wiring and connectors: Check for any loose or damaged wiring and ensure that all electrical connections are secure and clean. Repair or replace any damaged components as necessary.
  3. Test the injector: The resistance of the injector coil should be measured to determine if it falls within the manufacturer's specifications. If it is outside the acceptable range, the injector may need to be replaced.
  4. Test the ECM: If the injector and wiring are in proper working condition, the ECM should be tested to ensure it is supplying the correct voltage to the injector circuit. If it is determined to be faulty, it may need to be replaced or reprogrammed.

It is recommended to seek the assistance of a professional mechanic or dealership to diagnose and repair the P0273 code. They will have the necessary tools and expertise to accurately diagnose the issue and perform any required repairs.


What are the symptoms of the P0273 code?

  • Engine misfire or rough idle
  • Loss of power or acceleration
  • Decreased fuel efficiency
  • Increased exhaust emissions
  • Engine stalling or difficult starting
  • Illuminated check engine light (MIL) on the dashboard


What causes the P0273 code?

The P0273 fault code is specific to the Cylinder #5 Injector Circuit Low. This code indicates that there is a problem with the fuel injector circuit in cylinder #5, leading to a low voltage condition. Here are some possible causes for this fault code:

  1. Faulty fuel injector: The fuel injector in cylinder #5 may be faulty, causing low voltage or a poor electrical connection.

  2. Wiring issues: There may be a problem with the wiring harness or connectors associated with the fuel injector circuit. This can include issues such as a short circuit, open circuit, or damaged wiring.

  3. Injector driver circuit problem: The injector driver circuit, which controls the operation of the fuel injector, may have a fault or malfunction.

  4. Engine control module (ECM) problem: The ECM, also known as the engine control unit (ECU), may have an issue that is affecting the fuel injector circuit in cylinder #5.

  5. Fuel supply issues: Insufficient fuel pressure or a problem with the fuel delivery system can cause issues with the injector circuit, leading to a low voltage condition.

It is best to have a professional mechanic diagnose and repair the P0273 fault code, as they will have the necessary tools and knowledge to properly diagnose the issue and replace any faulty components.

Possible Solutions

How to fix P0273?

To fix the P0273 fault code, which indicates a problem in the cylinder #5 injector circuit being low, you can follow these steps:

  1. Check the injector wiring harness: Inspect the wiring harness for any signs of damage or loose connections. Repair or replace the wiring as necessary.

  2. Check the injector connector: Ensure that the injector connector is properly plugged in and securely connected. Clean any dirt or debris from the connector pins.

  3. Test the injector: Use a multimeter to test the resistance of the injector. Compare the reading to the manufacturer's specifications. If the resistance is out of range, replace the injector.

  4. Check for injector clogging: Use an injector cleaning kit or have a professional clean the injector to remove any clogs or deposits.

  5. Inspect the fuel system: Check for any issues with the fuel system, such as a clogged fuel filter or low fuel pressure. Clean or replace the fuel filter and test the fuel pressure to ensure it is within specification.

  6. Check the fuel injector driver circuit: Consult the vehicle's service manual for the correct procedure to test the fuel injector driver circuit. This may involve using a diagnostic scan tool or a power test tool.

  7. Test the engine control module (ECM): If all else fails, the issue may lie in the ECM. Have a professional technician perform a thorough diagnosis to determine if the ECM needs to be replaced or reprogrammed.

Remember to clear the fault code from the vehicle's onboard diagnostic system after performing any repairs. If the P0273 code reoccurs, further diagnosis may be necessary.