P0271 Fault Code

Long Description

Fault code P0271 is logged when the powertrain control module (PCM) has detected a malfunction with the fuel injector for cylinder 4.

This code means that the voltage signal from the cylinder 4 fuel injector circuit is too high. This code is part of a series of fuel injector codes specific to each cylinder. These codes run from P0261 up to p0296.

Fuel injection systems spray fuel vapors into the cylinders of an engine to improve efficiency and performance. By introducing the fuel as a vapor, combustion can more readily take place in the cylinder.

These systems became standard in all vehicles after 1990, meaning most vehicles can have this fault code, especially because most vehicles have at least four cylinders.

Manufacturers like Citroen, Peugeot, and Ford are some of the most commonly associated with this fault code.

Other Signs of This Problem

Issues like this can have fairly noticeable symptoms when it comes to the operation of the vehicle.

In most cases, the most obvious sign will be the presence of the Check Engine light on the dashboard. This is not always a given though.

The vehicle will also run poorly. This can include rough idling and stumbling when accelerating.

The vehicle can also misfire. If a misfire occurs, it is likely that P0304 will be logged, indicating a misfire in cylinder 4.

What Could Be The Problem?

The causes for this issue will likely be found close to the fuel injector for cylinder 4. If there are other fuel injector codes logged, it is possible the cause will be found upstream in the fuel system.

One of the most likely issues is that the fuel injector pressure sensor is faulty.

Additionally, there may be a fault within the fuel injector pressure sensor circuit. These can be issues like damaged or frayed wiring or loose connections.

A blockage in the fuel injector for cylinder 4 can also cause a spike in pressure, resulting in an excessive voltage signal.

In rare cases, the PCM could be at fault or running on outdated software. This will likely come with various other fault codes being logged though.

Fixes

Fixing this issue will focus on any issues with the cylinder 4 fuel injector and the fuel injector pressure sensor circuit.

Adding a fuel cleaner additive to the fuel tank can help break up any restrictions within the fuel injector, allowing the pressure to regulate.

If there are any faults in the pressure sensor circuit like damaged wires or loose connections, they need to be fixed.

If the pressure sensor itself is faulty, it must be replaced.

If the fuel injector is defective, it needs to be replaced. If the fault codes for various fuel injectors have been logged, the fix will be found upstream.

If none of these issues are present, it can be the PCM itself. Check for software updates. If the PCM is defective, it must be replaced.

Seriousness

Fault code P0271 should be considered a serious issue, especially if the engine is misfiring. A misfiring cylinder can cause damage to other components within the engine.

It is recommended to have this issue be fixed immediately.