How Long Does Battery Need To Be Disconnected To Reset ECU?

How do I reset my car after replacing the battery?

Al, I am not sure about foreign cars, but for most US cars, you should connect the battery and then turn the key but not start for about 10 to 15 seconds.

Then, once all sensors reset, start the car and just let it sit and idle for 15 to 20 minutes without touching anything.

Then all should be fine..

What would cause a car to not start with a new battery?

If your vehicle won’t start, it’s usually caused by a dying or dead battery, loose or corroded connection cables, a bad alternator or an issue with the starter. It can be hard to determine if you’re dealing with a battery or an alternator problem. Here’s how to know which one is the culprit.

How do I reset my ECM?

How to Reset a Car ComputerOpen up the hood.Remove the positive terminal cable from the battery using your pliers or wrench.Go to your fuse box in your car, and look at the diagram. Select the fuse that is labeled “ECM” and remove this fuse. … Keep the car disconnected like this for two to three minutes to clear the computer’s memory.

How do I reprogram my ECU?

Programming overviewConnect the vehicle interface cable to the OBD-II connector and turn the ignition switch to ON.Open the ProECU software and choose Tools then Detect Vehicle.Select Program Engine ECU.Choose Query ECU to identify the ECU version fitted to the car.More items…

Does a used ECU need to be reprogrammed?

Yes. In fact, if you want to change the ECU for any reason, a dealer will have to reprogram your keys into the ECU.

Will disconnecting the battery clear fault codes?

Leaving the battery disconnected for about 15 minutes will ensure the vehicle systems will completely reset when you reconnect the battery. Secure the negative cable back to the terminal and cover it with the cap (if applicable). Disconnecting the battery will clear the error codes and reset the check engine light.

What are the signs of a bad ECM?

A bad or failing ECM may produce any of the following 5 symptoms to alert the driver of a potential problem.Check Engine Light Turns On. An illuminated Check Engine Light is one possible symptom of a problem with the ECM. … Engine Stalling or Misfiring. … Engine Performance Issues. … Car Not Starting. … Poor Fuel Economy.

How long does it take for a car computer to reset?

The readiness monitors will remain until the car has been driven long enough for the computer to evaluate the various system and sensors. The amount of time can vary based on the vehicle. In some cases it can take up to 100 miles for all of the computer monitors to completely reset.

Do I disconnect the positive or negative to reset ECU?

When removing cables, remove negative first, then positive. If you just want to reset the ECU, removing only negative is good enough. When installing cables, install positive first, then negative.

How do I reset my ECU without disconnecting the battery?

Easy Way to Reset ECU without battery disconnect With the key in your pocket/car, push the Engine Start button TWICE (so the car is fully on, but not started) Within three seconds of the car “ON” (again NOT started), Floor (all the way down) and Release the gas pedal fully 5 times within 5 seconds.More items…•

What happens if you unplug the ECU?

However, if the ECU is unplugged, it will retain any charge it may have even if you create a power draw someplace else in the vehicle. So you’d need to wait a decent amount of time to be “sure” it’s drained. Some folks go so far as to unplug the battery and let the car sit over night.

Which battery cable do you remove to reset the computer?

How to Reset a Car ComputerOpen up the hood.Remove the positive terminal cable from the battery using your pliers or wrench.Go to your fuse box in your car, and look at the diagram. … Keep the car disconnected like this for two to three minutes to clear the computer’s memory.

Does disconnecting the battery reset the ECU?

Will disconnecting battery reset ECU? Can a ECU be reset? Yes, all ECU (Engine Control units) can be reset and be should reset once per manufacturer’s guideline for a smooth relearn process or upon installing a replacement unit.