belcom

iTrader: (1)

Just thought I'd share the info for those who don't want to wait 3 days after header install for the ECU to readjust. And disconnecting battery is never a good thing as well. So I guess this is a safer and quicker way.

This is out of the Mitchel On-demand:

Acura 3.2 TL/CL/MDX/Integra
ECM/PCM Reset Procedure

To reset ECM/PCM without scan tool, turn ignition off. Remove BACK UP or Clock/Radio (7.5 Amp) fuse from underhood fuse/relay box for 10 seconds.

CleanCL

iTrader: (4)

I'm guessing that fuse powers the ECU? If it does, what is the difference between disconnecting the battery and this? And why wouldn't the ECU take the same amount of time to readjust?

belcom

iTrader: (1)

Well see from experience, I once disconnected the battery on my Audi. The next day it ran fine for half a day and then stalled in the middle of the intersection. I was lucky the car was manual so I moved out of the intersection easily however the engine would shut down if the foot is not on gas permanently. I was trying to figure out what the problem was for a month, with 3 mechanics not being able to tell me what's going on. Basically what sometimes happens when battery is disconnected bad codes are written to the EPROM in the computer and interfere with the operation of the vehicle. I didn't back then that I could just short 2 particular contacts for 5 seconds and resolve the problem. So $500 and a month later I read about the ECU reset and guess what, problem solved. From that time on it's a big no no to disconnect the battery.

gto2050

As long as you disconnect the NEGATIVE lead, it should cause no problems. That's what I did when I installed CAI on both cars. No issues.

02AV6

The same procedure (clock/back up fuse) just different location is also used on 6th. gen AV6. It's been used for the following:
a. IF CEL light is on and you need to erase it.
b. If mods installed, you need to reset ECU.

power3dfx

even though i feel that disconnecting that battery is fine, this is another way that could be useful if you dont have tools around.

allmotor_2000

The proper way is to remove the backup/clock (7.5A) fuse. However you need to do the 'idle learn' procedure else it will idle wierd especially as weather changes and you turn the A/C on and off.

BlackV62K2

This is the first I've heard of the 'idle learn' procedure. Procedure to reset the ECU on V6P.net is just disconnect the (-) and pull the backup/clock fuse (7.5A) for a few minutes. Put the fuse back in and re-connect the cable. Let the car warm up and take it for a easy drive for about 30 mins or so for the ECU to re-learn.

BlackV62K2

Taken from

3. Do the ECM/PCM idle learn procedure:
• Make sure all electrical items (A/C, audio, rearwindow defogger, lights, etc.) are off.
• With the HDS, do the ECM/PCM RESET and CKP PATTERN CLEAR.
• Turn the ignition switch to the ON (II) position for 30 seconds.
• Start the engine, and let it warm up to its operating temperature (the cooling fans cycle twice).
• Let the engine idle (throttle closed and all electrical items off) for 10 minutes.

4. Do the low-rpm CKP pattern learn:
• Test-drive the vehicle on a level road: With theA/T in the Sequential Sportshift mode and insecond gear, or the M/T in second or third gear, decelerate (with the throttle fully closed) from an engine speed of 2,500 rpm down to 1,000 rpm.
• Stop the vehicle, and put the transmission into Park or Neutral. Set the parking brake. Do not turn off the ignition

6. Do the high-rpm CKP pattern learn:NOTE: The low-rpm CKP pattern learn must be completed before you do the high-rpm CKP patternlearn.
• Test-drive the vehicle on a level road: With the A/T in the “L” position, or the M/T in first gear, decelerate (with the throttle fully closed) from anengine speed of 5,000 rpm down to 3,000 rpm.
• Stop the vehicle, and put the transmission into Park or Neutral. Set the parking brake. Do not turn off the ignition.

BlackV62K2

^ Taken from

Got a question, say you just installed an intake. You reset the ECU and immediately take it to the dyno without the ECU completely re-learning all the parameters. Will that affect the dyno number?