proper way to reset ECU - Mazda 6 Forums : Mazda 6 / Mazda Atenza Forum

mahzda6 · 10-19-2009, 05:36 PM

I want to reset the ECU in my 2004 mazda 6 but when i disconnect the battery terminals there is no change to the rpm's when i start the car nor when i drive for a bit. The rpm's used to go crazy when i disconnected the battery but no longer. Any ideas why?

cheers.

blue06mazda6 · 10-19-2009, 05:52 PM

Disconnecting the battery will reset the ECU.
Sometimes mine runs like crap and almost stalls if the AC is on right after reconnecting the battery.
But then other times it runs fine.

Mojar7070 · 10-19-2009, 07:13 PM

i've read somewhere here that the full reset is: Disconnect battery and then pump the brake pedal 3 times. true or no??

sp33dy6 · 10-19-2009, 07:14 PM

QUOTE (Mojar7070 @ Oct 19 2009, 04:13 PM)

Quote:

i've read somewhere here that the full reset is: Disconnect battery and then pump the brake pedal 3 times. true or no??[/b]

LMFAOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO OOOO!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!

seigfredm · 10-20-2009, 03:24 AM

QUOTE (Mojar7070 @ Oct 19 2009, 04:13 PM)

Quote:

i've read somewhere here that the full reset is: Disconnect battery and then pump the brake pedal 3 times. true or no??[/b]

I just disconnect the battery, wait few minutes and reconnect it

ttshark · 10-21-2009, 10:29 AM

You have to wait a full minute for reserve power to drain. However, ECU takes 10 minutes doesn't it?

All I know is most of the crap I do takes more than 10 minutes anyway so its a guaranteed reset.

seigfredm · 10-21-2009, 01:40 PM

QUOTE (ttshark @ Oct 21 2009, 07:29 AM)

Quote:

You have to wait a full minute for reserve power to drain. However, ECU takes 10 minutes doesn't it?

All I know is most of the crap I do takes more than 10 minutes anyway so its a guaranteed reset.[/b]

I was actually thinking of keeping the key/ignition in ON position to make sure all residual power is gone but I'm not sure if there's a drawback in doing that.
what do you think? coz if we disconnect the battery while everything's off there's nothing to use up the remaining power not like when the system is on then disconnect it, it will surely eat up whatever's left......

am I making sense?????

FORZDA 1 · 10-21-2009, 01:45 PM

QUOTE (seigfredm @ Oct 21 2009, 01:40 PM)

Quote:

I was actually thinking of keeping the key/ignition in ON position to make sure all residual power is gone but I'm not sure if there's a drawback in doing that.
what do you think? coz if we disconnect the battery while everything's off there's nothing to use up the remaining power not like when the system is on then disconnect it, it will surely eat up whatever's left......

am I making sense?????[/b]

You see, this is why some of the shop manuals tell the technician to step on the brake to discharge any remaining voltage from the ECU capacitors...

Mojar7070 · 10-21-2009, 01:56 PM

QUOTE (FORZDA 1 @ Oct 21 2009, 10:45 AM)

Quote:

You see, this is why some of the shop manuals tell the technician to step on the brake to discharge any remaining voltage from the ECU capacitors...[/b]

this was what I meant by pumping the brake pedal a couple of times, to discharge any leftover voltage. I knew I wasn't crazy.

seigfredm · 10-22-2009, 01:45 PM

QUOTE (Mojar7070 @ Oct 21 2009, 10:56 AM)

Quote:

this was what I meant by pumping the brake pedal a couple of times, to discharge any leftover voltage. I knew I wasn't crazy.[/b]

there's no stupid or crazy questions only stupid answers

so the shop manual actually instructs the tech to step on the brakes, all the while I thought when you disconnect the battery none of the circuits will close.
I guess I have to reset my ECU again, the proper way.
What do you think about leaving the ignition ON then disconnect?

10-19-2009, 05:52 PM	#2 (permalink)
blue06mazda6 Track Racer Join Date: Aug 2006 Location: Middletown, PA Posts: 571 Thanks: 0 Thanked 0 Times in 0 Posts Groans: 0 Groaned at 0 Times in 0 Posts iTrader: 0 reviews	Disconnecting the battery will reset the ECU. Sometimes mine runs like crap and almost stalls if the AC is on right after reconnecting the battery. But then other times it runs fine. __________________ 06 6 I\| Xm Radio\|Stubby Antenna\|Silverstar turn Signal bulbs (Front)\|6 1/2 speakers in front door\|6 x 8 in rear\|Wing Spoiler\|Black OE Tail lights\|4 Brake light mod\|Side markers converted to flash\|18 x 7.5 MB Boost rims\|Remote Start\|LED Map and Door lights\|Sport Grill\|Auto Dimming Mirror\| MS Springs\| JDM Visors\| K & N SRI\|Sony HU\|12 in. Infinity Sub @ 400 RMS\|Removed Door moldings\| Car Pics

10-21-2009, 10:29 AM	#6 (permalink)
ttshark Track Racer Join Date: Nov 2008 Location: Sydney, Australia Posts: 405 Thanks: 0 Thanked 0 Times in 0 Posts Groans: 0 Groaned at 0 Times in 0 Posts iTrader: 0 reviews	You have to wait a full minute for reserve power to drain. However, ECU takes 10 minutes doesn't it? All I know is most of the crap I do takes more than 10 minutes anyway so its a guaranteed reset. __________________ 2002 Mazda 6 Limited series 1 Manual 2.3L I-4 Australian Model (Jap Spec) 10:6 High Compression Current Mods: BC Racing Coilovers \| Injen CAI \| Advanced Timing \| Dark Yellow Smoked Fog Lights \| 18" Mazda RX-8 Wheels on Bridgestone GIII 225's \| Raybrig 4500K Pure White Parker/licence/door Bulbs imported from Japan \| Audiolink ipod Connection \| Fluoro Orange Rocker Cover \| Custom Grounding Kit \| Breather Air Filter \| Apexi Turbo Timer \| PCV Oil Catch Can (Still need to install) \| RDA Front Slotted Rotors \| ACRE Super Fighter Pads \| NGK Plug Wires \| 6-SMD Red Interior Map Lights \| Honda S2000 Gearknob Coming SUPER soon: HIDs (Freight Container Arriving Soon) \| Front/Rear Strut Bar \| Exedy Stage 1 Sports Organic Clutch \| Exedy Lightened Flywheel Coming soon: F2 Supercharger kit \| F2 Header \| Custom 3" Catback Exhaust System with High Flow Cat \| Complete Haltech Tune

10-19-2009, 05:36 PM	#1 (permalink)
mahzda6 Drivers License Join Date: Jun 2008 Location: Vacouver, BC Posts: 93 Thanks: 0 Thanked 0 Times in 0 Posts Groans: 0 Groaned at 0 Times in 0 Posts iTrader: 0 reviews	I want to reset the ECU in my 2004 mazda 6 but when i disconnect the battery terminals there is no change to the rpm's when i start the car nor when i drive for a bit. The rpm's used to go crazy when i disconnected the battery but no longer. Any ideas why? cheers.

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10-19-2009, 07:13 PM	#3 (permalink)
Mojar7070 Track Racer Join Date: Aug 2007 Posts: 103 Thanks: 0 Thanked 0 Times in 0 Posts Groans: 0 Groaned at 0 Times in 0 Posts iTrader: 0 reviews	i've read somewhere here that the full reset is: Disconnect battery and then pump the brake pedal 3 times. true or no??