I've searched the forum and can't find anything that is close to the problem that I'm having.

Just bought a 2011 Lexus GS450H. It wasn't running when I bought it and was prepared to replace the hybrid battery since the information screen showed Check Hybrid System.

Well, I got the hybrid battery replaced and now I have the READY light but the engine won't start. Doesn't even crank.

When the tech had finished replacing the battery he drove the car down the driveway so I know its not the inverter.

I hooked up a techstream mini vci to the car and the only code I got was a P2237 which is an O2 sensor on bank 1 upstream of the catalytic converter.

Would that code keep the car from cranking? It won't even turn over.

My guess its something else, but I'm not sure where to start troubleshooting.

If I could find a schematic that shows how the hybrid/starting system works I could probably figure it out, but haven't been able to find one.

I bought the car for $2700 with only 82k miles on it and its immaculate inside.

Any help you guys could give me would be awesome.

Just don't need a 4200lb paper weight.

Thanks in advance!


Bret

 

Did you try flooring it in park, or driving it at all? O2 codes won't stop the car from running, and you do have the READY light on...

In addition, your scanner might be unable to read HV ECU codes - basically anything battery/etc-related.

 

The car was driven on electric power only about 250-300 ft so I know the electrics are working. I figured that the O2 code wouldn't keep the car from running, but its the only code I have.

What if the O2 sensor had a dead short? Could that stop everything?

I've been looking for a wiring diagram or a schematic or something. There just isn't that much out there in the public domain.

Thanks for your reply!

BTW, do you know how the car starts? Nobody, including Lexus, lists a starter as an available part.

 

No need for a "starter" - the transmission does that.

Mostly everything here applies:
http://prius.ecrostech.com/
The gs450h has a two-speed automatic connecting MG2 to the driveshaft (hence the electric auxiliary oil pump), other than that it's mostly the same principles.

The car doesn't "crank" - the engine just starts... whenever the car wants it to. The engine generally starts up for awhile when the car is cold, to light up the catalysts and to bring the coolant temperature to over 40 celsius - if the car's "hot enough", it won't do this. If the battery's low enough (state of charge <40%), it will also start to force-charge. If you require any significant amount of acceleration (basically more than around 10kw at the wheels - limit depends on temperature and other things), it will also start - you can slowly crawl on electric. Over a certain wheel speed, the car will again keep the engine running, albeit in fuel-cut mode.

A disconnected O2 just means that the car will run in open loop mode. The engine should still start.

Again, "turn it on" and floor it in "park" - the engine should fire up. To be honest, if you haven't attempted to start it again for so long, it should fire up upon "ready" regardless

I wouldn't try keeping the car in "ready" mode, though - if it's in "ready" and full throttle in park doesn't start the engine, something else is wrong. In other words - don't needlessly discharge the HV battery, because it can get expensive fast

 

Thanks so much for you reply.

I don't have good news to report about my car.

It is a 4200 lb paperweight.

Turns out the guy I bought it from filled the car with fresh oil.

He did that because a lot of the oil leaked out...when the engine locked up and punched a hole in the side of the block!!!

I understand that you buy a car as is, but this is obvious fraud.

The oil was new, so there was no indication of mechanical failure.

I will be contacting an attorney to get remuneration.

Appreciate your help in teaching me more about this car.

Not sure what my next step is going to be...replace the engine or part the car out.

Why can't people just be honest?

Have a good one!

 

If you do decide to keep the car and get a new engine, a 2nd gen IS350 or 3rd gen GS350 (non-AWD) donor should do it... at least based on a quick look. Keep your old one to swap things like the water pump belt tensioner & etc.

Good luck!

 

After many months of slowly disassembling and carefully re-installing I'm proud to announce that the car lives!

The engine runs flawlessly and I'm working out some of the remaining bugs.

Funny, after all of the work, the P2237 code is still there.

I didn't replace the O2 sensor when the engine was out.

It took so long to remove the engine and transmission because I was traveling for work.

The service manual leaves much to be desired in the whole process.

Required a ton of common sense mechanically and a lot of prayer for the electrical side!

Learned a lot, the car is awesome.

Only thing I'm working through right now is a rumble or roar in the drivetrain, which I think is associated with separating the propeller shafts.

If thats not it, I don't know what it is.

Not sure if I would attempt it again, but its done now.

 

You can remove both O2 sensors without taking off the engine, but the inverter (and power steering ECU) will have to be taken out in order to reach the one on LHD cars' passenger side (bank 1, I believe).

What were the issues on the electrical side?

 

Congratulations on completing the engine swap. That's a big job! I thought I got ripped off with my car which required a 12v battery, hybrid battery and a new set of wheels to get to where ti should be. Great car though, now I can drive and enjoy it! I hope that you can now enjoy yours. Did you document the swap at all?

 

When you try to crank it in park after it is fix. Does the engine move?

 

Great job on doing the swap. Was the donor engine from a GS450H or a GS350?

Asking cuz unfortunately I need to replace the engine in my 450H. And I'm unsure if the GS350 engine is the same, less the accessories and I am assuming the bellhousing.

 

yes it will work, I have done it.