Greeting from UK..Am the proud new owner of Lexus sc430, not many of these cars on the road and was wondering if anyone has any idea where the pre cat bank 1 sensor plug is.
can gain access to sensor but can’t work out where to plug the lead in..Any help gratefully received
Thanks

 

It's been a while... but I think it's right behind the alternator? There's should be a small metal bracket behind the alternator connected to the block right above the oil pan line. That's where the connector is.

And congrats on your new SC430! Glad to have another owner on the forums. As much as you can drive with the top down and enjoy the open air motoring. Also, using the center shifter to keep it in 2nd and 3rd gear to wind the 4.3L V8 out it the way to maximize the fun. Be safe out there!

 

Thanks for reply…just been under car again and I think your right, can see a metal plate with 2 bolts and just about get my fingers in there To feel the plug ( so awkward to get get to ) Think I’ll have to hire 4 post hoist to work on it.
Yes..love driving with top down but rains quite a bit in London..
As the for the V8 very smooth & has the auto gear box and aspirated vvt engine .. areal joy to drive

 

Welcome to the forum Thefather, from another UK member. Lots of good stuff on here and many knowledgable people.
Cheers
Steve

 

Good evening..Well update from last week..hired the 2 post lift ready to change pre cat sensor, and went to petrol station to fill up with petrol..on way home car showed red battery on dash..2. Minutes later whole car closed down..no engine , no electrics …nothing..
Got the AA to check car..and found out electric short somewhere..suggestion from mechanic it could be Alternator..
Was going to unplug that and see if battery still shorting out but no idea where it unplugs from..
Any one with any ideas..
Thanks

 

It definitely sounds like the alternator. Those are all the symptoms. And after all, you probably disconnected it to get to the O2 connector. My guess is you didn't plug it in all the way or you forgot to connect the battery cable.

It sounds like you were running off your battery alone for 2 miles and then it died, stopping your car.

 

Regrettably this was a separate issue as have not started doing the sensor yet…Waiting for weather to improve before doing anymore work on car..& will be taking out alternator fuse to try to isolate the short..See what happens then
Thanks for trying to help

 

It is most likely your alternator.

Alternators going out are somewhat common on this car because of a leak in the Power Steering reservoir hose. They display the symptoms you described.

Here is an easy test:

Take your battery out and charge it

Put it back in and start your car.

Use a volt meter and check the battery terminals.

If they are above 13.3 Volts (In the 14 V range is better) then I am wrong and your alternator is fine.

But if they are only in the 12 range, your mechanic and I both agree it is your alternator

You can also buy one of these if you don't have a voltmeter

 

Thanks for reply…If only it was that easy….Unfortunately the moment battery is plugged in it drains it completely in seconds
The same happened when auto guy plugged his jump .start battery in…There’s a definite short somewhere and I’m hoping it’s the alternator doing it..Just waiting for weather to improve before I can remove fuses from alternator to try to isolate it and then see if car still shorting..This car will not fit in my garage so I have to work on it outside..
Thanks again for reply.
PS,,,,are there many of the SC 430s on the roads where you are ?

 

Thanks for posting this item, for that price (I actually paid $6.51 with NJ tax) I just ordered one, figured it would a great addition to my jump box and battery tender I keep on hand for my 2008 SC.

 

if you get the battery fully charged, and it's a good battery, it'll be able to run the car for 15-20 minutes. Make sure nothing is draining it down like headlights or the stereo. once the car is running, you can use a multi meter to track down where the alternator power is being interrupted. Start at the main output on the back of the alternator and verify the voltage is around 14.4V. put your ground on the engine block and then follow the cable back towards the battery. You have probably got a bad alternator. But the engine ground strap could be disconnected or something. So you want to check both sides of the battery. Uf you have to replace the alternator, plan on the power steering pump and the P/S hoses at the same time. A set of valve cover gaskets is probably needed to. But that usually takes care of all the fluid leaks for several years. Good luck

 

Thank you all for your replies…What I would like to do first is simply unplug the alternated ..
Looked at taking out the main alternates fuse but seems that in it self is not simple task.
Can anyone please advise where the alternates unplugs from..And can the plug be removed without dismantling half the car..
Many thanks from novice mechanic

 

See picture. Use a multimeter. The big post is where the main 12V+ (hot) from the battery is going. The post should be covered in a rubber grommet and held on by a nut. Then you use the chassis as ground (like in every car). Then see what voltage you're getting at the alternator. Be careful because the alternator pulls a lot of amps, lol, don't bridge the hot (12+) volts to the chassis directly.

 

If he unplugs the plug and disconnects the red wire, that does what he wants, right?

It's not quite as easy as using an alternator checker, but it would allow him to run the car off battery for a few minutes. (Though it will die quickly, since the alternator is not running)

 

Just take out fuses 49 and 53 under the hood
https://fusecheck.com/lexus/lexus-sc...0-fuse-diagram