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ECU (Engine Control Unit)

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How Your ECU Uses Sensor Data
Today’s Today’s modern vehicles are made up of anywhere from one to seven computers that assist with the car’s day to day functions. An engine control unit (https://www.yourmechanic.com/article/how-your-ecu-uses-sensor-data) (ECU), is a computer that similar to that of a laptop or...
How Your ECU Uses Sensor Data
Today’s Today’s modern vehicles are made up of anywhere from one to seven computers that assist with the car’s day to day functions. An engine control unit (https://www.yourmechanic.com/article/how-your-ecu-uses-sensor-data) (ECU), is a computer that similar to that of a laptop or...
How Your ECU Uses Sensor Data
Today’s Today’s modern vehicles are made up of anywhere from one to seven computers that assist with the car’s day to day functions. An engine control unit (https://www.yourmechanic.com/article/how-your-ecu-uses-sensor-data) (ECU), is a computer that similar to that of a laptop or...
How Your ECU Uses Sensor Data
Today’s Today’s modern vehicles are made up of anywhere from one to seven computers that assist with the car’s day to day functions. An engine control unit (https://www.yourmechanic.com/article/how-your-ecu-uses-sensor-data) (ECU), is a computer that similar to that of a laptop or...
Industry News for Automotive Techs: October 29 - November 4
Toyota and Getaround's smartphone key, future McLaren cars, DMCA car hacking, a fire at Ford's headquarters, and Chevrolet's SEMA 2016 show cars.
What Is a Reprogrammable ECU?
The The ECU, or engine control unit, is part of your car’s computerized brain and is responsible for monitoring and managing all aspects of engine operation. For anyone who isn’t interested in upgrading their car for higher performance, the stock...
How Your ECU Uses Sensor Data
Today’s Today’s modern vehicles are made up of anywhere from one to seven computers that assist with the car’s day to day functions. An engine control unit (https://www.yourmechanic.com/article/how-your-ecu-uses-sensor-data) (ECU), is a computer that similar to that of a laptop or...
How Your ECU Uses Sensor Data
Today’s Today’s modern vehicles are made up of anywhere from one to seven computers that assist with the car’s day to day functions. An engine control unit (https://www.yourmechanic.com/article/how-your-ecu-uses-sensor-data) (ECU), is a computer that similar to that of a laptop or...
How Your ECU Uses Sensor Data
Today’s Today’s modern vehicles are made up of anywhere from one to seven computers that assist with the car’s day to day functions. An engine control unit (https://www.yourmechanic.com/article/how-your-ecu-uses-sensor-data) (ECU), is a computer that similar to that of a laptop or...
How Your ECU Uses Sensor Data
Today’s Today’s modern vehicles are made up of anywhere from one to seven computers that assist with the car’s day to day functions. An engine control unit (https://www.yourmechanic.com/article/how-your-ecu-uses-sensor-data) (ECU), is a computer that similar to that of a laptop or...
What Is a Reprogrammable ECU?
The The ECU, or engine control unit, is part of your car’s computerized brain and is responsible for monitoring and managing all aspects of engine operation. For anyone who isn’t interested in upgrading their car for higher performance, the stock...

Related questions

After replacing the ECM in a 2002 Mercury Mountaineer what will be the reason for it not to fire or start
On cars built after the late 1990's, replacing an ECU is a much bigger deal than just plugging in a new box. The ECU has to recognize the serial number of the car and the other modules in the car....
question
The security system warning light should not illuminate once the vehicle is started and you are driving. If the light does illuminate, that means there is a malfunction in the security system. Obviously, if this problem started immediately after you...
Car starts but will not run
You should not replace any parts, at all, unless the part is diagnosed as not functioning. ECU's rarely fail (fully 50% of warranty returns on ECU's have absolutely nothing wrong with them). If there is a spark at the plug...
can I use the positive and negative posts under the hood to maintain power to the computer while replacing main battery
If the two posts are indeed specified for jump starting, then the answer is "yes" you can safely install a 12 volt car battery there at the remote posts while you remove and replace the permanent car battery. Electrically, all...
ECU disconnected
Hi and thanks for contacting YourMechanic. First, remove the ground cable from the battery and let it stay off for 12 minutes. Then hook up the battery cable and retry the key. If your vehicle still gives you the same...
Replaced ECU Integrated Transfer Case Board, how much will it cost to reprogram it?
Hey there, thanks for writing in about your 2006 Land Rover LR3. Unfortunately, this is a specialized service only available through Land Rover service centers, and not a cost estimate readily available to us here at YourMechanic. I recommend requesting...
module or unit?
Hi there. From the description you have provided, your vehicle Check Engine Light on with lots of warnings and exterior lighting acting weird, sounds like there may be a charging system related problem (https://www.yourmechanic.com/services/electric-problems-inspection). I would recommend not driving your...
Hello, my car has no spark, no controlled ground for the fuel pump, and no injector pulse. Fuse link close to the battery and relays are good.
Hello and thank you for contacting YourMechanic. The ECU is under your passenger's side seat. You can gain access to it by simply sliding the seat all the way forward and removing the plastic cover from the ECU. You can...
Check Engine Light does not come on even though there are trouble codes present
The pink/light green wire in ECM pin 2 on the connector will ground the wire internally to the ECM to turn on the Check Engine Light. You could test the wire with the key on and it should have battery...
Missing/Broken ECU - 1989 BMW 325i
If your ECM is failing (https://www.yourmechanic.com/article/symptoms-of-a-bad-or-failing-engine-control-module-ecm) or has failed, it shouldn't be extremely difficult to find a good shop to rebuild or replace them. There are a number of electronic rebuilders who rebuild ECMs (w/warranty). Also, there are a number...
What Is an ECU and What Does It Do?
The electronic control unit (ECU) used in today’s cars and trucks is used to control the engine and other components’ functions. An ECU is a computer with internal pre-programmed and programmable computer chips that is not much different from a...
No crank/no start
Hello there. No start conditions are one of the most common faults. If the car will not communicate with the OBD-II DLC port, then this typically means there is a fault between the connector and the ECU. This could be...
How long can it take an ECU computer to go bad?
Hello, and thank you for writing in. The vehicle likely did not suddenly develop all of these problems. Oil leaks in particular happen due to excessive engine wear. The spark plugs and their coils tend to be regular maintenance with...
It won't start and the ECU is not found by scanner.
Hi there. First check the battery and make sure that there is 12.6 volts. If the battery is low, then the battery will need charged before testing again. Check the wiring from the battery to the fuse box and make...
My car has crank and no start issues.
There is one thing I don't think you have listed or have checked. That would be injector pulse. You can have fuel pressure but without injector pulse from the ECU, the injectors will not open and the cylinders will not...
Will a bad O2 sensor damage my car's computer?
The engine control unit (ECU) is a possible cause of the O2 sensor (https://www.yourmechanic.com/services/oxygen-sensor-replacement) fault codes but not the most likely. Your vehicle is equipped with 4 O2 sensors. Bank 1 is the driver's side. Bank 2 is the passenger...
Traction control light is on, 2000 BMW
As you know, your car is equipped with wheel speed sensors at each of the four wheels which monitor wheel speed while relaying this information constantly to the ABS and traction control system which are controlled by the car's ECU....
Air conditioning light - 2001 Honda Civic
Hi there, check the A/C relay for being stuck in the "On" position. Relay contacts degrade over time and use, and can stick together when burned. The result would be the A/C light staying on, even though you press the...
Intermittently doesn't start
Hi there. There could be several reasons for your vehicle's intermittent no start issue. From the description you have given, I would not think the ECU (electronic control unit) is your vehicle's problem. Assuming the ECU is not recognizing the...
If a mechanic put one of the fuel injectors in the wrong cylinder, could this damage the ECU?
Hello. The ECU could not have been damaged by moving injectors to different cylinders. The injectors are not programmed to be in a particular cylinder of the engine. Having only two injectors reconditioned is the most likely cause for running...

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