Proud owner of a 97 Ls400 here. But since i've owned it, the A/C hasnt worked, i knew this going in, but a new AC condensor came with the car when i bought it, just had to be installed, so I installed that, got some freon put in there, but the compressor wont kick in. The A/C fan turns on, just no cold air. I'm not getting voltage to the connector on the compressor and the compressor wont engage. I opened up the ECU, cuz i read a thread (all my crazy lexus issues solved thread) listing symptom's and i have a few of those, like sulphur smell occasionally, jerks when i manually shift from 1st to 2nd sometimes, no obd communication, and of course a/c compressor failure. Anyway i opened up the ECU, no capacitors seem to be leaking. I read that theres a place i can send my ECU into to get it tested for 40 bucks after shipping. Is it worth it, while i have it accessible or am I barking up the wrong tree? Also i put the test light on some fuses, i have a diagram for the 96 LS here and when I put the light on fuse 6 which is the A/C system and rear window defrogger, the light wont light, also with fuse 11, which also has to do with the AC system, but when i replace those fuses with a brand new 15 amp, they still dont light.. Is there something i'm missing here? cuz some other fuses arent lighting up, but those seem to work fine. What is my next step, or what should i do next? Should I send in my ECU cuz the 97's are known to have some issues with capacitors, some were wobbly/loose, does that affect anything? a few tower looking cylindrical ones was kinda tilted so i adjusted it to stand up straight, and yea it was real touchy/weak. Idk if that has anything to do with anything. But whats the next thing I should try?
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Plug an OBDII scanner in and verify that it can read the ECU and any codes it has stored. Looking for leakage below the caps is the main thing since you had it out and open. Going that far having the caps on hand to replace would have been ideal.
R134A is the proper refrigerant for the A/C system. If you put Freon, that may be part of the issue.
The jerking may be related to other issues, pull any codes and let us know.
alright, yea i plugged the scanner in, it linked up this time, but no codes were/are stored. As far as under the caps, what do you mean by that? i looked at the caps, didnt see any obvious leakage. but i didnt like lift them or anything. also 134a is whats in there, my bad. also the ecu is still accessible, i didnt put the panels back on yet, just in case i wanted to get back in there
A couple of thoughts:
1. Follow the procedure posted by Yamae to check for ripple before spending any money.
2. The caps may well be failing without any externally visible evidence.
3. Once any cap leaks, you have a relatively limited time before the corrosive fluid will damage the traces on the printed circuit board. This would be either expensive or impossible to fix.
4. You may wish to find a second ECU for testing purposes and to replace the caps before you swap it n. Hopefully, you could source one from the local junkyard (a.k.a. recycler).