Reset Ecu

[sleptema]

If I leave the battery disconnected for the whole night will do the job of resetting the ECU?

My car v35 coupe it's not starting completely, everything works fine a part than starting ON.!!!

Helppppp...!!!

If your car isn't starting, you should probably rule out the start circuit before you play around with the ecm.

Battery has >12 v with everything off?

Battery AND starter have >10.5 v while cranking?

Start wire has ~12 v whilst trying to crank?

I would check these first. If these are all correct, try giving the starter a light tap with a hard faced hammer - if it then starts, you need a rebuild.

[sonicii]

Not many ECUs these days use volatile RAM, so disconnecting the battery isn't going to reset anything. You need either a consult type tool, or one of the manual (stop watch and hold your tongue right) methods above.

Depending on the fault, CELs will often clear after several 'start and run' cycles without any faults detected. The code will be stored, but the light on the dash goes out.

All the ECU learns is long term fuel trim, this isn't going to stop your engine starting.

[scotty nm35]

Good chance the crank sensor is dirty or faulty if the car isn't starting when cranking. If it's not cranking that's a different fix.

[Allfather]

On 10/4/2010 at 5:42 PM, TUFF_350 said:

Hey guys,

did a bit of a search but came up empty. Google turned up this:

ECU Resetting Procedures

Timing is extremely critical. If it is NOT DONE within the specify time, the ECU will not reset and the Check Engine Light (CEL) will continue to remain ON. A stop watch or an analog clock with a second’s needle will be useful.

Operations Procedures

1. Confirm that accelerator pedal is fully released, turn ignition switch “ON” and wait 3 seconds.

2. Repeat the following steps (2a and 2b) procedures quickly five times within 5 seconds.

2a. Fully depress the accelerator pedal (HARD).

2b. Fully release the accelerator pedal.

3. Wait 7 seconds, fully depress the accelerator pedal and keep it for approx. 10 seconds until the CEL starts blinking.

4. Fully release the accelerator pedal (while the CEL is still blinking)

5. Wait about 10 second.

6. Fully depress the accelerator pedal and keep it for more than 10 seconds.

7. Fully release the accelerator pedal (The CEL light will continue to blink).

8. Turn ignition switch to “OFF” position and now you can start the car. The CEL light should be gone.

If the CEL light continues to remain ON, repeat the above steps. Timing is EXTREMELY critical to resetting the ECU.

Edit: Added the "Easy Method" for ECU Reset

The Easy Method:

After experimenting with different timing, and reading posts by other members, I've come up with a condensed method of doing this reset. This method works EVERY time, even w/o a stopwatch. I've used this method successfully a dozen times, or so, now w/o a watch. After a few times, you won't need a watch or instructions. You'll get so darn good at it, you'll find yourself doing it while waiting at a traffic light.

Timing is not as critical with this method...no stop watch needed. Just count in your head...one-one thousand, two-one thousand, etc, or use stop watch. The most critical step is step #3....wait 10 sec, instead of 7.

1. Ignition "ON", count to 3.

2. Depress/Release pedal 5 times...hard and fast.

3. Count to 10 (not 7!) and fully depress pedal

4. Count to 12 (SES should be blinking), release pedal

5. Count to 10, depress pedal

6. Count to 10, release pedal.

7. Turn off ignition, then start engine. Done!

Will disconnecting the battery be an even easier option? Or does anyone have another procedure lol? Thanks.

Hi guys. I have 2005 skyline 250gt and i have to reset throttle, i followed this procedures, but there is nothing blinking (SES, or MIL)
Can anybody tell why???

[V35_Paul]

On 4/5/2017 at 4:28 AM, Allfather said:

Hi guys. I have 2005 skyline 250gt and i have to reset throttle, i followed this procedures, but there is nothing blinking (SES, or MIL)
Can anybody tell why???

the "Check Engine Light" should blink at step 3. If not start again