AndyLexusF

Greetings from hot florida again. Can someone give me some advice on what is happening with my 94 ls400. Out of the blue, the rpm's dont go over 1500. It just drops back down when it gets that high. I ran a diagnostic, and it was code 41. TPS sensor. I replaced the TPS with a clean used replacement from a U-pull it. No difference what so ever. Could be a 2nd faulty part, but I doubt it.
Any ideas? could it be a fuse? or another sensor?

Thanks in advance/
Andy

djMaru

check ur fliter box and injectors might be bad.

Fili400

My vote is ECU. Sounds like your car is going into "limp mode".

AndyLexusF

Limp Mode, after researching it more, seems to fit the prescription. Before I started changing things like fuel pumps, relays, and cleaning throttle bodies.... I decided to reset the battery. Just removing the negative for 30 seconds didnt work previously. So I left it off all day. And I got in it last night and it reved!!
I will test drive today. But I believe that might have been it!

Thanks all for the advice.

williamb82

ecu, i just solved this exact problem. replaced the tps, checked the tps wiring, all good. sent the ecu to ate to be rebuilt, they failed to fix it. sent it back under warranty, same result. bought a used ecu and now it runs perfect.

Yotarip

^ William is right. I had the exact same problem and 41 trouble code (1993 LS400). I checked EVERYTHING. Even had brief hopes of the problem being solved only for the problem to resurface a few miles later. The only thing that fixed my problem was REPLACING the ecu. Sending my bad ecu out for the FIX didn't fix it.

It seems that the 90-94 LS400 ecu's have an expiration date of 10-15 years.

PureDrifter

iTrader: (10)

more like 15-20 years.

7schulz

Why does Toyota suck at ECU's my 95LS had a bad ECU and it sounds like my 93 land cruiser could have a bad ECU at some point(not b.c of this thread, different forum).

skyther

I had this issue with my LS when I first got it; it would buck everytime I went over 2k RPM. Like you, I tried swapping the TPS and had no improvement. Swapped out the electrolytic capacitors in the ECU and voila, problem solved.

williamb82

i think replacing the caps is all that ate did, and it did not fix it. there was 1.7v on the tps signal wire with the plug disconnected. it should of read 0. i told them this each time. they havent got a clue whats wrong or how to fix it. they just replace caps and hope that the leaking caps values being off was the problem. sometimes it is, most times it isnt. and getting a refund from them is proving to be impossible, when i gathered the info they requested, they then just request more. its ridiculous.

PureDrifter

iTrader: (10)

chargeback.

guys, how exactly does toyota "suck" at ECUs? your 15-20 year old cars with complex electronics have a relatively (given the total number of LS's still running fine) small number of ECU failures due solely to AGE.

the '95 had a recall on its ECUs, and unfortunately some of the original owners never had the work completed under warranty.

7schulz

Should have been done right the first time. Thats all I'm saying. Both of the vehicles are their flagship vehicles and they both have ECU problems and neither are from age. The ECU should never go out of warranty that is a non wear item. It's the brains of the car and causes many things to work(or not work) and very expensive to replace.

Edit: never go out of warranty for programing issues.

RA40

iTrader: (6)

As good as silicone is, we as computer users are aware what happens over time with electronics. The car is out of production, to expect a lifetime warranty is unrealistic. The electronics in the ECU are subject to wear-cycling just as light bulbs have. Some parts may not be up to it and if these issues are coming up 15+ years later...Toyota designers achieved the mail goal. Sucks for the owner but if this were occurring with frequency in the first 5 years/100K then, they would have responsibility. Beyond that...too many variables to concern themselves over.

7schulz

They both are documented early life failures hence the TSB/warranty of these ECU but they stopped warrantying them after 5yr/50K miles I believe.

PureDrifter

iTrader: (10)

yeah, super-realistic view this, to expect every component on every vehicle made by a manufacturer (and all the manufacturers who they contract out to) to be utterly perfect and last the lifetime of the car.

what people never realize is that just because something's electronic and made of silicone tin and copper is that its still an automotive PART, it has certain tolerances it has to achieve in a working lifespan, and it has a FINITE lifespan. there is wear and tear, from elemental causes depending where the car is, to internal stress from repeated heat cycling, to a million other things.

it lasted in your (#$*ing car for 15 (#$*ing years without a (#$*ing problem. IF by some miracle it was broken within a reasonable time of purchase from NEW, Lexus REALIZED IT, fixed it, gave you a rental, and filled up the (#$*ing GAS TANK.

i dont see anyone complaining about replacing (#$*ing 15 year old suspension components, or engine components, or the occasional filter, or even spark plugs, or any other WEAR ITEM.....