P1235 Fault Code

Long Description

Fault code P1235 is a manufacturer-specific code that is logged when the powertrain control module (PCM) has detected an issue with the fuel pump system.

This happens when the PCM has detected that the signal from the fuel pump control circuit is out of the allowable range.

This system is responsible for controlling the fuel pump. This means a malfunction with its circuit can cause improper fuel supply to the combustion chamber, causing the engine to run lean.

The fuel pump is a vital component in providing flow for the fuel, allowing it to leave the fuel tank and enter the fuel injection system.

Be sure to see fault code P0230 as this is a very similar generic fault code for this issue.

Despite being a manufacturer-specific code, P1235 represents the same issue for a huge number of manufacturers. The most notable of these include Citroen, Ford, Peugeot, Mercedes-Benz, Mazda, and Toyota.

Other Signs of This Problem

There can be a number of noticeable symptoms when it comes to issues with the fuel pump.

The most obvious sign will be the presence of the Check Engine light on the dashboard.

It is possible the fuel pump will be unable to operate at all. This will result in the engine running excessively lean or not starting at all. Running lean is the term used to describe an engine with too little fuel in the air-fuel mixture.

Be sure to look out for codes like P0171 that can indicate this condition. There may be other fuel pump codes like P0231, P0232, and P0233 logged as well.

What Could Be The Problem?

Because the PCM has detected the signal from the pump control module, the cause will likely be found within the circuit itself. This makes the cause electrical in nature.

One of the most common causes of this issue is a failing battery. This can result in the voltage for the fuel pump controller being too low.

A faulty fuel pump can also lead to this issue. Additionally, a faulty fuel pump relay can be the cause.

Other potential causes include damaged wires or loose connections in the circuit. These can cause an open or short circuit condition within the fuel pump control circuit. A blown fuse can also be the cause of this issue.

Fixes

Fixes for this problem will typically be found within the fuel pump control circuit itself.

One of the first steps is to clear the code and perform a road test. This is done to ensure the problem is actually there.

Any faults in the circuit for the fuel pump control circuit need to be fixed. Loose or damaged connections and damaged wires need to be repaired. A blown fuse in the fuel pump relay should also be replaced.

A faulty fuel pump must be replaced.

A faulty battery should also be replaced if it is detected.

Seriousness

Fault code P1235 should be considered a moderately serious issue. It can prevent the vehicle from running at all.

This means it is important to have this issue resolved immediately to resume the proper function of the engine.