Never Ignore These Vehicle Symptoms –They May Indicate a Bad Engine Control Module
Automobiles today can cost as much as a starter home. There are good reasons for this sticker shock, though – they are as different from older cars as a smartphone is to the old rotary dial phones. They also last far longer; cars from before the 1980s mostly became junk by the time they racked up 100,000 miles, whereas a new car bought today and properly maintained can easily last double that. They’re also far more reliable during those miles, to the everlasting horror of tow truck drivers.
At the heart of your car is its brain: the digital engine control module, also called an ECU or ECM (and other terms in an occasionally confusing way). In all seriousness, automobiles today should be called smart cars, because they basically use the same underlying technology as smartphones and provide some of the same functions. Usually found under the dashboard or behind the glove compartment, it provides all the functions the old analog powertrain controls did and adds many more.
The ECU Grew Out of a Definite Need
Prior to the 1980s, vehicles used a range of methods for controlling their functions. All of them were analog until the 1970s, when early microprocessors first hit the commercial market. However, the early digital ones were not very sophisticated, and processor and memory chips were incredibly expensive until the 1980s, so few vehicles used digital technology before then.
The older analog methods worked surprisingly well for the needs back then. They used a combination of vacuum pressure and careful timing based on engine revolutions to control all the engine functions. Yet, as electronics advanced, the need for precision finally pushed manufacturers into installing early engine control modules. Ford started mass producing automobiles using an ECU predecessor called an electronic engine control in 1975, and by the mid-1980s, the cost of microprocessors had dropped so much that it was cheaper to use them than not.
The ECM Is a Bit of a Genius
Technically, the powertrain control module (PCM) is the main computer in your car. However, most manufacturers combine the ECM and transmission control unit (TCM) into one. Even that is somewhat misleading, since the TCM and ECM still use separate chips, but for most circumstances, unless you are a electronics expert needing to get into specifics, the ECM and PCM can be considered on most cars as the same thing.
Regardless, the engine control module is a smart cookie. It takes data from hundreds of factors that are detected by a series of sensors throughout your vehicle and combines them into a useful base of information. This happens several hundred times a second!
Then a highly-advanced algorithm compares each factor to a database built into its memory and determines how it should run the powertrain that instant to get the most efficiency and greatest power without causing damage to the engine. Some of the adjustments it makes are
- Air to fuel ratio
- Ignition timing
- Idle speed
- Electronic valve control
Emissions and Vehicle Efficiency Depend on a Functioning ECM
The engine control module uses a smart lookup table that provides ideal values for each condition throughout the expected range of that vehicle’s typical operations. Without the tables or a smart device to evaluate and adjust the operation constantly, today’s cars wouldn’t be much more efficient than in the past. In 1979, the average new vehicle got less than 13 miles per gallon of gasoline; in 2018, it was almost 25 MPG. The ECU is responsible for much of that increase.
A modern ECM allows for a higher compression ratio, far more precise spark timing for an ideal burn and a better idle control. If a high-performance programmable ECU is installed, a computer is used to monitor the exhaust and power output so your engine can be digitally tuned to its ideal output.
Using the exact ECU designed for your car’s powertrain (and any customized upgrades) means you’re assured to maintain the optimal engine performance, achieve greater fuel efficiency and produce less pollution. This is how automobile manufacturers have increased horsepower while decreasing fuel consumption. Some aftermarket accessories, including turbocharging, exhaust modifications and transmission upgrades, may require a programmable ECM. If your module is not programmable, you might have to purchase a new unit.
If Your Car Has Any of These Symptoms, Check the ECU
Once an engine control module starts going bad, it can cause damage internally. All the experts agree that as soon as an ECM exhibits signs of malfunction, it needs to be replaced sooner rather than later. If you’re aware of the symptoms, you can save yourself a heap of trouble! However, the ECU may appear bad when it’s actually a broken sensor, which receives most of the vibrations and wear, so make sure your sensors are working before buying a new engine control module.
The most obvious – and most common – early sign is the check engine light coming on. While there are a few possible causes of this, it should never be ignored. Pay particular attention if the indicator comes and goes, as this is normally associated with the ECU.
Other signs are somewhat less specific, since they can be caused by a range of troubles. If the engine is backfiring or stalling during idle, it could be a sign of a bad engine control module. Again, if it’s intermittent, it’s more likely to be caused by a malfunctioning ECU than most other potential causes.
A rattling sound while the engine is idling or during times when it needs more power, such as pulling a heavy load or climbing a big hill, can indicate the engine is misfiring. A bad ECU might be misreading the sensor information or not accessing the correct lookup tables, which can make the rattling sound. It can also happen while idling as well.
If you believe your ECU needs replacement, Importapart has a huge range of parts covering most vehicles on the road today. Even if the engine control module is aftermarket, they can usually help you find the precise one to meet your custom needs as well. You need to get the exact module to fit both your OEM engines and any powertrain upgrades, or else your vehicle won’t run correctly. Importapart has expert mechanics select the best manufacturers and suppliers to find the perfect combination of lowest price and highest quality.