The ECM (Engine Control Module) is sometimes also called an ECU (Engine Control Unit). However, most engineers and technicians will say ECU stands for Electronic Control Unit. Is there a difference? Not much. The ECM (Engine Control Module) is a specific type of ECU (Electronic Control Unit). In modern normal cars, you may have over 40 ECUs, and in modern luxury cars over 150.
What Does an ECU / ECM Do?
- ECU (Electronic Control Unit): ECUs are microcomputers. The various ECUs are connected to your Volvo’s onboard computer system. They continually monitor and regulate your car’s different systems and components and report back performance data or malfunctions to the computer. Each system has sensors, which send data back to the ECUs. On the other hand, the ECUs regulate various systems via actuators. The various ECUs regulate your Volvo’s engine, the HVAC (Heating, Venting, Air Conditioning) system, brakes, doors, and a myriad of other systems.
- ECM (Engine Control Module): The ECM is one particular type of ECU. The ECM controls, monitors, and regulates the engine. It is obvious now why the ECM is an extremely vital component of the car.
Signs the ECM is Failing
When the ECM starts to fail, it’ll affect the performance of your Volvo. You’ll notice overall reduced efficiency. Here are some signs to watch out for.
- CEL or MIL Gets Activated: the first indication that there may be some problem with the ECM is if you notice your Volvo’s Check Engine Light (CEL) or MIL (Malfunction Indicator Lamp) on your dashboard has turned on. The light might flicker or continuously stay on. Either way, it is indicating some issue that needs to be checked. The only way to check this is to use a specific type of scanner that professional garages have. This diagnostic tool can read the error codes the computer is throwing, and a professional mechanic can decipher the problem and suggest a solution.
- Poor Performance: Some displays of a malfunctioning ECM are rough idling, decreased power, and even stalling. This means the ECM is no longer being able to manage the different systems it is responsible to control and regulate. It could be any number of issues, such as ignition timing, fuel mixture, or other complications.
- Drop in Gas Mileage: If you notice a sudden decrease in fuel efficiency, this could mean a faulty ECM.
- Problem with Ignition: If your Volvo struggles to start or after starting it promptly stalls, this could point to a problematic ECM, as it manages the car’s startup sequence.
- Transmission Issues: If your Volvo is experiencing transmission problems like unexpected shifting or delayed gear changes, it might be because the ECM is having problems communicating with the TCM (Transmission Control Module), which is another ECU.
- Arbitrary Error Codes: When multiple MILs (Malfunction Indicator Lamp) get activated, that could also be because the ECM is malfunctioning and cannot communicate with the other systems. You might notice warnings regarding traction control or your anti-lock braking system (ABS). This could happen if the ECM sensor is failing. However, the only way to be sure is to have professional diagnostics done using the correct scanning tools.
- Failure to Communicate with the Scanner: The diagnostic tool that professional mechanics use is called an OBD-II scanner or On-board Diagnostics-II scanner. It scans your Volvo’s different systems and then identifies and deciphers the various error codes your car is throwing. A professional mechanic looks at these and triages the different issues. However, if there is a catastrophic ECM failure, then your Volvo might not even be able to communicate with the scanner. This is a complex situation, and under these circumstances, the diagnosis should be done by a trained and certified mechanic.
What We Do
At World Class Auto Repairs, we are certified and trained professionals who have many years of experience in this. We will approach the problem methodically. Not only will we use our state-of-the-art diagnostic tools, but we will also do visual and physical inspections. We will look at all the wiring and connections and uncover any damage that may have occurred due to corrosion. We have both the equipment and the know-how to attack a failing ECM challenge.
If you suspect your Volvo might have an ECM issue, don’t wait to call us! This is something you need to address quickly. Call or email us, or better yet, stop by our shop in Boca Raton, Florida.