ecm reset.

[pyaaw!]

Hello everyone,
I have an '08 renza
I have found a few threads that tell you to disconnect the ground and push the brakes/or turn on the headlights. well if you disconnect the ground the lights will not turn on. so how do you really rest the ecm?

[7-even]

your supposed to disconnect the batery and step on the brakes to drain out the stored power

[pyaaw!]

this is exactly what i did, so you can tell me if i did it wrong.
1-disconnected the battery(ground)
2-held the brake pedal (did not see my brake lights on, at all)
3-waited 15-30 minutes
4-reconnected the battery
5- started the car, did not see the speedo jump up to 70mph, like someone said

then,
to be sure i fully disconnected the battery and did steps 2-5. but i waited about 3 hours, this time. still no speedo jump.

also i noticed my radio kept the all my presets, does that mean anything?

thanks ahead of time for the help

[7-even]

i think you have to disconect the pos cable. i dont have the link to the thread right now

[Zipper]

radio has capacitor to help keep the presets.
When I reset mine, it never jumps

[jurupa]

When ever I reset my ECU my speedo jumps to 60 and stays there for a sec or two and drops. My radio presets also go away. But then again I believe the 05 Reno's have a different radio than the 04 and 05 Forenza's. I don't know about 06+ tho.

[pyaaw!]

ok thanks everyone. i guess i will have play with it to see if i can find anything different to show it has been reset.
Thanks again

[phatslaya]

Ok. So i've reset my ECU a few times by taking the ground off. It has seemed to work everytime so this time after reading the forum i decided why not take the positive off and see if it does the whole speedometer reading and what not. Well after i took the positive off, I now have a check engine light :@. Guess ill have to take the car to the dealer so they can take the CEL away.

[jurupa]

Originally Posted by phatslaya

Ok. So i've reset my ECU a few times by taking the ground off. It has seemed to work everytime so this time after reading the forum i decided why not take the positive off and see if it does the whole speedometer reading and what not. Well after i took the positive off, I now have a check engine light :@. Guess ill have to take the car to the dealer so they can take the CEL away.

Thats a good way to short out the car assuming you are leaving the negative side on.

[phatslaya]

Oh shit. What does this mean ?