Reset icu

[Jonbooker44]

hi all 

 

Been thinking of remapping engine and or gears on a lexus 300 rx 

 

I read somewhere if you take of the negative lead from the Battery it resets icu ..is this correct .

[rich1068]

Resetting not remapping?

You're correct. Disconnecting the negative terminal for a time should make the ECU forget the adaptations it has "learnt". But check your handbook for the reconnection/immobiliser procedure first.

[steve2006]

Yes, removing the Battery lead and leaving it a few minutes will reset the engine ECU but also bear in mind various other items may also need resetting after doing so like one touch windows, sunroof and radio stations ( if your radio requires a security code either disable it first or make sure you have the code).

As far as I am aware remapping any Lexus ECU is not possible, there are some aftermarket alternatives available for earlier cars like a Mines ECU but unsure on later models. 

[rich1068]

There are probably a couple of fuses you could pull instead of disconnecting the Battery, like on my GS. So you don't lose settings. But I'd have no idea which on an RX.

[Jonbooker44]

Yes your correct I will take a look at that option,  might save alot of hassle 

[steve2006]

I think it is normally the EFI fuse usually located in the footwell box.

The radio code disable method should be in the owner’s manual, if you don’t have it you can download a free digital copy from Lexus.

[Jonbooker44]

Thank you guys for the invaluable advice .

I pulled put the appropriate fuses and left them out for 3 minutes .

 

Put them back in .

 

I started the engine,  which it did first time , as some people report that I doesnt start first time after a reset.

Im not 100% sure but gear changes might appear to be smoother ...

 

They say over the next 1000 miles it will adapt to how I drive ....

 

Many thanks again