There’ve been hundreds of words written on the subject of resetting the ecu and I thought I’d heard them all, but when I saw a post recently referring to “the EFI fuse, #38” and another referring to the ecu fuse as a 5 amp, I thought WTF? If either of these is right (I don’t think that they are) – then I’m pulling the wrong fuse and the improved response I “thought” I felt was all in my head. I thought I may want to verify that I’ve been resetting the right one - a search finds countless references with few actual fuse locations - and a few of them wrong.

I’ve been pulling the one that’s identified as ECU-B1 on the label inside of the fuse box cover – it’s the 20A at the bottom left of the fuse box right above the 40A MAIN. In the 1999 owner’s manual, it’s identified as number 32, fuse ECU-B1, 20A, but the circuit description doesn’t give a clue, only mentions windows, door locks, remote, theft system, lights and clock.

This fuse will lose steering wheel position, radio settings, and clock – on my ’99 GS4.

If this is right, at least it’ll help newbies verify that they’ve got the right fuse – if it’s wrong – maybe more than a few of us will learn something.

My $.20 cents worth.

 

Garnet - That's the one I've been pulling for 2 years now & also the same one that my Lexus tech told me would reset the ECU. However, some of the members MAY have a different fuse box ( don't see how!? ) because a few of them have PM'd me claiming their unability to locate the same "ECU-B1" fuse. Can't see Lexus using 2 different fuse boxes. In fact, John ( jbrady ) & I were discussing whether or not the GS & LS share the same fuse box setup ( after checking around my dealer's lot, it appears so except that some of the fuses are labeled differently ). When all else fails, U can always disconnect the battery cable!!

 

That's the fuse I've pulled on my 2000 GS400. It doesn't cause my seat, radio or any other memory to be lost, but I only pull it for 2 mins or so, maybe that's why? Still has the desired effect on the engine ECU.

 

Bit - I think that's because you have Nav. I suspect there is an independent power source or flash memory that maintains waypoints, etc if the battery is disconnected.

 

That's the fuse I pull on my 01 GS430. You have to leave it pulled for about 30 min or so to lose all the seat memory and radio, etc. Otherwise as Bit said, you won't lose it, but I disagree with it clearing the tranny ECU. All has to be erased for it to be successful otherwise my car still retains the tranny ECU setting, along with everything else (seat, climate control and radio). That's my experience with the ECU to date. Granted I have the TC, so I can tell immediately if the clearing of the ECU was successful or not.

 

GS430GUY - I want to be sure that I understood what you're saying - are you saying that if you don't leave the fuse our for 30 minutes (or more) that the tranny ecu doesn't reset? And if that's so, you can rely on knowing that the tranny ecu is reset when you have to reset the clock, radio, etc.?

 

Garnet,

I personally assume nothing with regards to resetting the ECU. From my personal experience, when I have to reset my clock, seat, climate and radio. Only then do I feel that the tranny ECU has been cleared and I feel a difference when I floor my car compared to before. Once I didn't have the fuse out long enough, since clock, radio, etc were fine, I floored the car and it wasn't peeling out as it did the prior time when I had the fuse out longer and everything needed to be set. Others may disagree with me, but with my car, the above has worked time and time again. My rear tires can attest to that