Here is a brief look at a couple of reasons that would cause your ECM to go bad, including the symptoms to help you diagnose a faulty or damaged unit. Corrosion on the wiring harness and increased moisture are common causes of faulty ECMs.
What is the most common failure of an ECM?
The most common source of ECM failure is in one of the wiring harnesses. If the wires to the transmission or fuel injectors become corroded, they can lose conductivity, leading to a failure. Fortunately, these issues can usually be resolved by replacing the corroded wires.
What are the symptoms of a bad ECM?
Here are some telltale signs that indicate there's a problem with the ECM:
How does an ECU get damaged?
The ECU has seals around it which are supposed to prevent moisture from entering inside. Moisture is a bad thing to have in an ECU because corrosion will form on its components. If the corrosion is not cleaned away quickly, it will cause these components to get damaged. Then you will have a malfunctioning ECU.
Related Question What causes an ECM to go bad?
Will a bad ECM drain the battery?
A failed ECM power relay can also cause a battery drain or dead battery. If the relay shorts it can leave power on to the computer, even when the vehicle is turned off. This will place a parasitic drain on the battery, which will eventually cause it to go dead.
How can I reset my ECM?
Where is the ECM relay?
The relay is located in the engine main fuse relay control box. The defective ECM-power relay is removed from the control box by pulling it straight up and out of socket. The new ECM-power relay is installed into the socket and the engine scanned for codes.
What does PCM fault mean?
The P0606 fault code means that there's an error with your power control module (PCM). Your PCM is the computer inside your car that monitors all the vital systems. Basically, it's the brain of your car. It also runs a self-check, to make sure the PCM itself is working correctly.