Resetting ECU in Gen 5 Camry 2.4 - Toyota Nation Forum : Toyota Car and Truck Forums

cmathieu · 08-18-2007, 11:25 PM

Hi All,

I would like to know what the best way would be to reset the ECU in my Gen 5 Camry 2.4. I've been told by just disconnecting the battery and leaving it disconnected for about 1 hour will cause the ECU to be reset when I reconnect the battery.

Cheers,
Charles

LE05 · 08-18-2007, 11:31 PM

Quote:

Originally Posted by cmathieu

Hi All,

I would like to know what the best way would be to reset the ECU in my Gen 5 Camry 2.4. I've been told by just disconnecting the battery and leaving it disconnected for about 1 hour will cause the ECU to be reset when I reconnect the battery.

Cheers,
Charles

you were told correctly. sometimes it takes less than an hour, sometimes more.

cmathieu · 08-18-2007, 11:39 PM

Thanks for confirming LE05...might just leave it disconnected for 1.5 hours just to be sure

geoff5093 · 08-19-2007, 07:37 AM

I've had mine disconnected for 10 minutes and it cleared it out before, but yes thats one way you can do it.

TRD VVTi · 08-19-2007, 01:08 PM

I've never seen it take more than a few minutes.

Sedan Man · 08-19-2007, 01:15 PM

Might be a stupid question, but what does that do? Resetting the ECU?

Just wondering

TRD VVTi · 08-19-2007, 02:13 PM

Quote:

Originally Posted by Sedan Man

Might be a stupid question, but what does that do? Resetting the ECU?

Just wondering

You can do it to clear codes and to delete any adaptive memory.

cmathieu · 08-19-2007, 05:45 PM

Quote:

Originally Posted by Sedan Man

Might be a stupid question, but what does that do? Resetting the ECU?

Just wondering

From my understanding, resetting the ECU will be particularly useful if you have minor modifications (eg. air intake, higher octane fuel). Once reset, the ECU will 'learn' all the current engine behaviour and adjust according to your mods and not what Toyota set during a service thereby in theory taking full advantage of your mods.

That's just how I understand. Feel free to correct me if I am wrong anyone

TRD VVTi · 08-19-2007, 06:47 PM

Quote:

Originally Posted by cmathieu

From my understanding, resetting the ECU will be particularly useful if you have minor modifications (eg. air intake, higher octane fuel). Once reset, the ECU will 'learn' all the current engine behaviour and adjust according to your mods and not what Toyota set during a service thereby in theory taking full advantage of your mods.

That's just how I understand. Feel free to correct me if I am wrong anyone

It doesn't reprogram the ECU. What Toyota set as the parameters for the programming are still going to apply. Your theory is flawed in that regard.

cmathieu · 08-19-2007, 06:50 PM

Quote:

Originally Posted by TRD VVTi

It doesn't reprogram the ECU. What Toyota set as the parameters for the programming are still going to apply. Your theory is flawed in that regard.

I see. Thanks for pointing that out. So then, does that mean that the ECU will 'adapt' to the mods and provide a better performance of some sort?

TRD VVTi · 08-19-2007, 10:58 PM

Quote:

Originally Posted by cmathieu

I see. Thanks for pointing that out. So then, does that mean that the ECU will 'adapt' to the mods and provide a better performance of some sort?

Yes, it will adapt to the mods. That doesn't mean that you'll get better performance though. The ECU is programmed to meet a set specification for it's programmed parameters.

Here's an example for you with my other car. It's a '95 Pontiac Firebird Formula. I can adjust the fuel pressure down slightly and the car will make more power. It won't make more power for long though. The computer sees that it's running more lean and will make the injectors stay open longer to compensate. Very soon, it's running exactly how it was before.

Many manufacturers use this same principle to "prove" that their product makes more power. The maker of my adjustable fuel pressure regulator could claim that it makes more power and then prove it with a dyno run. It doesn't really make more power though. The computer sees the difference and adjusts accordingly. The same thing can happen with an aftermarket CAI or SRI. If the diameter of the tube is slightly larger where the mass airflow sensor is, the car will get more air in that is known/measured by the computer. The car will temporarily run leaner. Soon the computer figures this out and will add more fuel to compensate. Leaner makes more power, but also can cause engine damage if run that way for long.

pIOUs · 08-26-2007, 08:44 AM

There are OBD2 forums that speak at great lengths about the ECU. Reseting will not make more power. Search Long-term-fuel-trim (LTFT) and STFT. It will cover all you need to know.