P0270 Fault Code

P0270 OBD-II Trouble Code Short Description

Cylinder #4 Injector Circuit Low

What does trouble code P0270 mean?

The P0270 fault code refers to a problem with the injector circuit for cylinder #4 in the engine. This code indicates that the voltage level in the circuit is below the specified range, meaning there is a low voltage condition.

The possible causes for this issue could be a faulty fuel injector for cylinder #4, a wiring or connection problem in the injector circuit, or a problem with the Engine Control Unit (ECU) that controls the injector operation.

To diagnose and fix the P0270 code, you can start by checking the wiring and connections related to the injector circuit. Look for frayed wires, loose connections, or any signs of damage. If any issues are found, they should be repaired or replaced.

If the wiring and connections are in good condition, then you may need to inspect the fuel injector itself. You can perform a resistance test on the injector to determine if it is functioning correctly. If the injector is faulty, it will need to be replaced.

In some cases, the problem may be caused by a malfunctioning ECU. If other diagnostic steps do not identify any issues with the injector or wiring, it is recommended to have the ECU inspected or reprogrammed by a professional.

It is essential to address the P0270 fault code as soon as possible to prevent any further damage to the engine. Ignoring this code could lead to decreased engine performance, misfires, and potential damage to other engine components.


What are the symptoms of the P0270 code?

  • Engine misfire or rough idle
  • Decreased fuel efficiency
  • Poor acceleration
  • Increased emissions
  • Illuminated check engine light (CEL)
  • Slight or significant decrease in engine performance
  • Vehicle may stall or have difficulty starting


What causes the P0270 code?

The P0270 fault code indicates a problem with the cylinder #4 injector circuit on a car. This code is specific to the fuel injection system and typically occurs when the voltage or resistance in the circuit is lower than the specified range.

Possible causes for this fault code include:

  1. Faulty injector: The injector itself may be malfunctioning, causing a low voltage or resistance in the circuit. This can result from internal wiring issues or mechanical problems within the injector.

  2. Wiring issues: There may be a short circuit or open circuit in the wiring harness connecting the injector to the engine control module (ECM). This can be caused by damaged wires, loose connections, or corrosion.

  3. ECM problem: The ECM, which controls the fuel injection system, may be malfunctioning and not providing the correct signals to the injector. This can be due to internal faults, software issues, or a faulty sensor input.

  4. Low fuel pressure: Insufficient fuel pressure can also cause a low voltage or resistance in the injector circuit. This can be caused by a faulty fuel pump, clogged fuel filter, or a problem with the fuel pressure regulator.

  5. Other potential causes: Other factors that can contribute to this fault code include a faulty fuel injector driver module, a problem with the fuel injector control module, or a malfunctioning fuel pressure sensor.

To diagnose and repair the P0270 fault code, it is recommended to perform the following steps:

  1. Inspect the wiring harness and connectors for any signs of damage or loose connections. Repair or replace as necessary.

  2. Test the fuel injector for proper operation using a diagnostic tool. This will help determine if the injector itself is faulty and needs to be replaced.

  3. Check the fuel pressure to ensure it is within the specified range. If it is too low, troubleshoot and repair any issues with the fuel system.

  4. Test the ECM and related components to ensure they are functioning correctly. This may require specialized equipment and expertise.

  5. Clear the fault code from the ECM and test drive the vehicle to see if the code reoccurs. If it does, further diagnosis may be required.

It is recommended to consult the vehicle's service manual or seek assistance from a qualified technician for an accurate diagnosis and proper resolution of the P0270 fault code.

Possible Solutions

How to fix P0270?

To fix the P0270 fault code, which indicates a low circuit condition in cylinder #4 injector, you can try the following steps:

  1. Check the wiring: Inspect the wiring harness connected to the #4 cylinder injector for any signs of damage, fraying, or loose connections. Repair or replace any faulty wiring as necessary.

  2. Check the injector connector: Ensure that the connector on the injector is securely connected. Clean any dirt or corrosion from the connector and terminals. Make sure there is proper contact between the connector and injector.

  3. Test the injector resistance: Using a multimeter, measure the resistance of the #4 injector. Compare the reading to the manufacturer's specifications. Replace the injector if the resistance is outside the recommended range.

  4. Check the injector power supply: Verify that the power supply to the #4 injector is within the appropriate voltage range. Low voltage can cause the P0270 code. If the power supply is inadequate, check the fuel pump or any related components for issues.

  5. Inspect the fuel system: Examine the fuel system for any clogs or restrictions that can cause insufficient fuel delivery to cylinder #4. Check the fuel filter, fuel lines, and fuel pressure regulator. Clean or replace any components that are obstructing fuel flow.

  6. Check the ECM/PCM: If all other steps have been exhausted and the fault code persists, there may be an issue with the Engine Control Module (ECM) or Powertrain Control Module (PCM). Consult a professional mechanic or dealership to further diagnose and potentially replace the ECM/PCM if necessary.

It is important to note that these steps provide general guidance, and specific repair procedures may vary depending on your vehicle make, model, and engine type. It is always recommended to consult the vehicle's service manual or seek professional assistance for accurate diagnosis and repair.