Common Signs of a Truck ECM Malfunction

Engine Control Module (ECM) Basics

The ECM is built for producing constant, on-the-spot adjustments to your vehicle’s engine. It manages the fuel-to-air ratio as well as engine timing; these are its primary functions. Your ECM also has to share crucial data with your Powertrain Control Module (PCM) and Transmission Control Module (TCM) that control gear shifting, anti-lock brakes, and traction control systems. An ECM Malfunction can be not only bad for your Freightliner, but dangerous as well.

ECMs go through a lot of work to process all these functions but in order to pull that off it relies on the feedback from loads of sensors. With that in mind, we will need to identify whether your ECM or a faulty sensor is causing the issue.

Common Signs of Failure

The “Engine Maintenance” Light Is On

A truck’s check engine light is often times ignored by most people as it usually is no more than a simple tire pressure sensor or oxygen sensor is broken. However, on occasion it can mean there’s a problem with your ECM; especially if the light is on in conjunction with some of the other problems to be discussed.

Truck Not Starting

Your engine’s fuel-to-air ratio is the most uneasy upon start-up. Since it is up to the ECM to control the fuel-to-air ratio it could be setting it incorrectly causing you to have to turn your key several times in order for your vehicle to start. This is a sign of ECM problems or engine trouble.

Rocky and Improper Shifting

When your ECM sends bad data in regards to appropriate shifting timing to the TCM, shifting becomes awkward. This can also cause your engine to quickly rev up or slack down.

Unexpected Fuel Economy Drop

The fuel-to-air ratio and engine timing also affect your fuel economy. If your truck’s gas mileage plunges in the time span of around 2 weeks your ECM or sensor attached to it could possibly be causing the problem. If your gas mileage falls throughout the course of a few years it would be best to see your mechanic since this likely wouldn’t be from an ECM.

Abrupt Loss in Acceleration

As mentioned earlier, your truck ECM and TCM (Transmission Control Module) work together for smooth adaptation in acceleration. Your TCM works at shifting but the ECM has the role of adjusting the throttle correspondingly giving us the smooth shifting expected from the transmission. However, when an ECM isn’t calibrating the throttle properly transmission shifting ends up being bumpy and uncomfortable.

Engine Misfires or Stutters

If you have a fuel-to-air ratio that is too high, your engine can misfire, and a lower fuel-to-air ratio causes stuttering during periodic failures to ignite. This can be caused by a faulty ECM making miscalculations or improperly adjusted engine timing.