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Sc400 transmission problem help I can’t fix it

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Old 03-31-24, 06:25 AM
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SC79
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Default Sc400 transmission problem help I can’t fix it

Hey guys I just picked up this car, runs fine but-

Problem: OD light flashing, 1st to second shift under 2k rpms, feels like it goes straight to third from first. Won’t down shift when I press the accelerator to the floor no matter what gear I’m in. Kinda hard shifts to 1st when coming to a stop

when it works: in manual mode will engage all gears (minus OD), or when I cycle the key on and off, Od light stops flashing and will get to about 2800rpms before shifting still what feels like into 3rd and falling on its face.

What I have tried: did a trans service with filter and it took about 4qts type iv fluid. Both shift solinoids( the ones I took out where not factory, but the previous owner said they never swapped them, so it has been done before just I don’t know when) adjusted the cable for the transmission on the TB to almost all the way tight, and played with the tps sensor on the intake. This fixed relatively nothing.

i have yet to check the ecu but that’s the next step. Say it’s not leaking, what else is there? I’m at a loss. Thanks in advance for any info or help you guys have!
Old 03-31-24, 05:17 PM
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SC79
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So here’s the ecu, looks a little leaky and a capacitor was loose or extra. Also looks like it’s been repaired before. Any suggestions?
Old 03-31-24, 10:02 PM
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LeX2K
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What's going on with those solder joints? If you can call them that. And I see cold solder joints elsewhere that ECU is in bad shape if it was my car I'd replace it.
Old 04-01-24, 05:01 AM
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SC79
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Originally Posted by LeX2K
What's going on with those solder joints? If you can call them that. And I see cold solder joints elsewhere that ECU is in bad shape if it was my car I'd replace it.
I thought it looked not right. So also for the trans to have already had this worked on, and the shift solinoids replaced, makes me wonder if they had the same problem and either got it fixed or just never could fix the issue. Like I said the guy I bought it from didn’t do any work to it minus maintenance, just drove it. They guy he got it from put coilovers on it, relocated the driver wheel well harness, and possibly did this and the solenoids. He got it from the original owners who only took it to Lexus for service, so that rules them out.
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