Any Lexus/Toyota techs in the house?

b1pig

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Wife is debating on taking in her parents' 03 LS430. Could be a good car... but its got issues.

Limped it home tonight and spent some time under the hood.
Throttle body will not respond to pedal.
TPS shows throttle blade movement on OBD2 app when blade opened manually.
Throttle pedal has 2 sensors.... both show same responses relative to pedal position.
I applied voltage to the stepped motor and blade opened electrically.

Seems like I have a ECU issue... and that looks like a common thing on these older Lexus and Toyota cars.
Anyone else out there gone through this?
If there is enough time tomorrow evening after work, I'm thinking about pulling the ECU and having a look inside. Removing and replacing bad capacitors is within my comfort level provided the board isn't too crowded.

Anyway.

Still not set on getting or even keeping this car. My driveway is overflowing as it is.
Might be a good car for our daughter later on, though.... ssssooooo.....o_O
 

RAU03MACH

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Ok
Remove throttle body and unplugging all plugs
Se if the blade on throttle body closes easy or with some resistance by hand
If no resistance by hand the throttle body is junk
I just went through this with a Nissan
When you buy a throttle body get all tps and other sencors with it
It will be calibrated together with throttle body
And that's about it
 

96blak54

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Same here with my Ford Transit connect. Apparently the throttle body is a high fail rate part with mine included. Ive seen the ford tech guy youtube break down the issue that causes the throttle body to fail. Its nothing mechanical. It was all electronic failure internally to the throttle body. Engine idled for crap and wouldnt rev or respond to pedal effort. Throttle blade was free and clear, easy movement.

The local parts store had a few new replacements on the shelf, if that doesnt say ford part failure. $180 for the new one, 4 bolts and ecu reset later, my van runs smooth.

Not knowing any different, when driving the van it consistently had the tip in throttle response that was next to dangerous. If you were a new driver to the van, this tip in response would scare the life out of you, but replacing the throttle body to the replacement has corrected this issue and is far more pleasant to drive.
 
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b1pig

b1pig

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So far, the throttle body and TPS have tested ok.
The other night I tried a couple of throttle relearn tricks on other makes just for giggles. Nothing changed obviously… but.. I though what the hell and pinned the pedal then started the car.

Sucker revved up to 5k and the engine matched pedal inputs for a minute or two with no hesitation. Dash lit up with all of the errors but kept responding to throttle inputs. As soon as I let it go to idle, it went back into fail safe.

I got on the phone with an ECU repair tech at one of the main shops that comes up in search. Told they guy everything I’ve done…. Harness checks out, TB responds to 12v from the ECM side of the harness. TPS tracks throttle plate when opened manually. Both pedal sensors work proper….. he said he’s never heard or this on a 430, but the later model ones will do it. He said the key is the “ circuit low” as the voltage comes from the ECM. On the later models it has been one of the IC Chips. The bad news is that is classified as an unrepairable fault since they can’t replace the actual chips on the board.

This model throttle body does not have a “clutch” on the throttle motor assembly, so it does open with little resistance.
 
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