SC400-V8

iTrader: (1)

Someone may have already addressed this, yes, fuel pump ecu. Get a used working one and put it in yourself, like I did in my 92 SC400, and you'll be fine.

SadSexus

So a fuel pump ecu is different from the main ecu? thanks

Yamae

No. There isn't any independent fuel pump ECU. You were just misled. The main ECU controlles the fuel pump.

Mr.Gs_GTE

Yes there is, that information is not misleading. The fuel pump ECU is in the trunk on the left hand side. Will be mounted on the upper walls of the trunk behind the panel covers.

Mr.Gs_GTE

Hey guys, sorry if this already beed discussed on here. There are way too many posts to go through every single one to fine the one issue. Anyways, I'm swapped a 1uzfe in a 94 pickup and the truck started fine after my writing was completed and on multiple occasions After that. No cel at first but I expected it to come on at some point since my sub o2 sensors weren't plugged in yet.

The cel finally came on after a day of running the truck on and off the the garage. When I went to pull the codes, I noticed the cel stayed lit and would not blink when I jumped the diagnostic terminals. At first I thought it was in my wiring but I did a double check and confirmed the wiring was fine. later on the truck started struggling to idle unless I kept my foot on the gas for a min or so and slowly let go.

I did some research and found this thread which directed me to the leaking caps. I took the ECU apart and inspected it as best as I could and found no visible leaks on the caps but I replaced them all anyways. Plugged the ECU back in and I found out I fixed the idle problem. It now starts and idles on its own. But the cel stayed lit at all times and wouldn't blink when I jump E1 and TE1. I'm out of options at this point and I'm thinking about getting a new ECU but would at least like to know if there is something else I could do. Any help will be appreciated!

Yamae

LOL. You are another guy who mislead others. You are showing a totally different car's manual. A LS400 has an ECU under the dash, you must understand that this is the LS400 Forum.

Mr.Gs_GTE

Again, this information is not misleading. The LS400 also have a fuel pump ECU, I pulled one off a LS only three weeks ago for the swap i'm working on right now. Both the Sc and LS have fuel pump ECU. The LS FP ECU is also in the trunk. The "ENGINE CONTROL MODULE" is under the passing side dash. Yes. But there is a fuel pump ECU.

djamps

Although they call it an ECU -- isn't it a resistor and a relay (in a box), ultimately controlled by the main engine ECU? Just wondering (from a purely technical standpoint).

SadSexus

I would also like to know this as I wasnt pulling any codes by the diagnostics.

dicer

What year manual is that picture from? There is no ecu for fuel pump on a 1990 for sure, didn't look at 92 info yet but I'm sure it also does not have it.
So they may have done that in 93 or just 94 I don't know. 95 and beyond who knows.
These cars and all new cars now made are stacked full of ECU's. ECU meaning electronic control unit.

A person can mistake the abbreviation ECU for Engine Control Unit.

Ultramiler

Just FYI, I contacted a company that rebuilds ECUs and they said my year range ES300 (1999) doesn't have a problem with Caps, but the processors do fail, so while they can't rebuild them they offer replacements. I had to send mine away to get the immobilizer chip transferred over and it ended up costing me $275 including the return shipping. Plugged in back in P1135 and P1155 came right back.... so much for the Lexus diagnostic flow chart telling me to replace ECU..

sayow

Does anyone on the forum still perform the ECU capacitor repairs? My 98 JUST started having an issue with the speedometer not working (only about 5-10% of the time) and if i remember this can be caused by leaky capacitors. No other symptoms yet, but i would like to get ahead of it.

Anyone that has any repair info, please PM. Thanks!

djamps

Try banging on the dash above it when it's not working (and you're moving at a decent speed of course!). If it springs to life like mine does it's not ECU capacitors. In my case, something hanging up in the instrument cluster. ECU capacitor problems on 98+ seem pretty rare.

TaninAuto

Hi, Tanin Auto Electronix here. We are vendors on the site and we repair clusters, ECUs, climate controls, clock displays and do odometer corrections as well as other services.

What is the model of the 98? Give us a call or we can PM and talk about the car and ECU repair.

Thanks!

bdazzler

That works on my 94 LS400. I think I've read it's due to the lubricant they used for the speedometers.

Refer to this thread, sayow: https://www.clublexus.com/forums/ls-...-not-work.html