How To Identify Subaru ECU Problems

Subaru ECUs are complex systems that help control your engine, transmission, and other systems. When an ECU fails, it can cause a lot of problems. This not only means that you have to pay for repairs but also that you may experience a loss in power or performance. Luckily, there are several common issues that may cause an ECU to fail, and they are easy to identify if you know what to look for.

Error codes ECU

The ECU is the engine control unit, a computer that controls the various systems in your Subaru car and helps it run properly. When something goes wrong with this computer, an error code is generated.

The most common errors are P0420-P0450, which indicates an oxygen sensor failure (this problem can be fixed without replacing the sensor). Some other common errors include misfires on all cylinders or uneven fuel distribution among cylinders, which may require replacing spark plugs and injectors, respectively. Once you’ve identified where you’re having problems in your Subaru’s engine control system (ECS), it’s time to take action!

Heat Related Issues

Heat can cause problems with every single component in the ECU. For example, an overheating sensor can run out of calibration and cause a fuel injection problem. Heat can also damage wiring, connectors, and solder joints inside your Subaru ECU.

If you’re experiencing trouble with a component that seems like it should be part of the ECU—like your transmission or engine control module (ECM)—then it may well be time to look at replacing your Subaru’s ECU instead of just diagnosing and fixing those components individually.

Corroded Connectors, Wiring Damage And Broken Connectors

Corrosion on connectors, wiring damage, and broken connectors are the most common causes of ECU problems. The corrosion can happen for several reasons, including improper storage or transportation of your Subaru. If you’re moving from one state to another, it’s important that you take care not to expose your car to extreme temperatures or weather conditions during transport. Wiring damage can occur from a number of sources, including corrosion (as mentioned above) or mechanical stress on the wires themselves due to poor installation practices or exposure to excessive heat while installed in your vehicle.

Before beginning troubleshooting procedures, you should also check any cables connected directly to the ECU itself for signs that they have been damaged or disconnected.

Loose Connections Or Poor Ground

A couple of things to look for when checking for loose connections or poor grounds. First, check for corrosion on the terminals of the ECU. If there’s water damage, it can cause decay which can lead to bad connections with other components in the system. You’ll need a multimeter and 10 minutes to test each terminal on your Subaru ECUs. You’ll also want to look at how clean your battery is; if it’s dirty or corroded, then that could be causing problems with your vehicle’s electrical system! Finally, if everything looks good, then take some time looking over all of your connections between sensors and computer modules – these can sometimes get damaged during installation or even wear out over time due to constant vibration (i.e., riding around town).


We hope that this article has helped you learn more about the Subaru ECU and how to identify problems. The best way to deal with these issues is to have an expert check things out as soon as possible. If you need clarification about what’s causing your Subaru ECU problem, call us. We’ll be happy to help!