KoSC300

Hey guys,
After a few years on CL hiatus, i jumped in and purchased an 07' GS450h w/133k miles. While i'm happy to be back on ClubLexus, I could use some of your help as the vehicle has a few issues.

When starting the car, the vehicle starts right up, but with "Check Hybrid System" and CEL Lights both on. Its throwing a P2797 code. Lexus diagnostics tells me that the Oil Pump Controller Driver is Malfunctioned (part# G1167-30021). They mentioned that the part either operates or cools the hybrid system. Does anyone have experience with this issue? or how to go about repairing it/installation?

I can drive fine for roughly 10-15min. After that, the vehicle goes into limp mode and a few additional lights pop up (VSC, etc.). The vehicle only allows me to drive a max of 50mph. If i keep going for another 5-10min, it limits me to 40mph. Each ~5min after that keeps going incrementally downward to a standstill. If i let the vehicle sit for awhile (1hr+), it'll start right up fresh again and cycle through as aforementioned.

Lexus quoted me $430 for the part. If you add labor, tax, and misc things, it comes to a total of $1156. I can find the part online for $315. It looks like it is located under the hood on the passenger side. Reference part# G1167 below.

KoSC300

So I changed out the oil pump controller today and reset the CEL lights, but the lights come back on when restarting the car. So unfortunately the new controller didn't fix the problem. Anyone else have any suggestions?

sonnyhood

just a quick google, P2797 also is referenced as a gearbox oil pump in other cars.
which is why its stopping drive.
maybe your gearbox oil is low, or burnt out, have you chcked this?
The dealer says its maintenance free, but a quick fluid change may help?
P2797:Auxilary Transmission Fluid Pump Circuit Performance (not a lexus code)
http://www.obd-data.com/p2797.html
P2797 OBD Code Definition:
Auxiliary Transmission Fluid Pump Circuit Performance

Let us know how you travel with this

Robertcave

Did you get any joy with your fault as a guy on our uk forum found that the bearing was worn and replaced for £7 i suppose 10 dollars yr money
he also had p2797 code
http://www.lexusownersclub.co.uk/for...loss-of-power/

razerlazer

Check out the UK forum. This is an excellent thread for a possible fix for this fault. It always amazes me how quick the dealers are to throw parts out that require very little to repair.
I know the reason why but I still shake my head when I read something like this.
It's the same with repairing computers and I would imagine most reasonably complicated appliances/machines/gadgets. The diagnostic process costs more than the fix.

KoSC300

Yeah, i'm on that UK thread as well, and Hayne's description is very helpful, but i dont understand the mechanics of the tranny that well. I'll see if i can send it to my mechanic.

Havent looked at the bearing just yet. But my shop took a look and ended up bringing in a lexus mechanic. They say that the Aux trans pump plug contacts were insufficiently touching, even though it was plugged in appropriately. This caused my aux trans pump to not work entirely, which in turn caused the trans fluid to heat up. When the fluid got to certain temps, it limited my driving until the fluid cooled better to avoid burning the trans fluid.

They swapped out the plug and the contacts are touching now. The pump is actually working, but there must be another issue. I can drive fine now in engine only (No hybrid), and the car is limited to 70mph. The trans fluid is no longer heating up and causing my car to go into slower versions of limp mode. I still also get the P2797 code. The above diagnostics and plug change costed me $600 thus far. I'll have them look at the bearing that Hayne describes and hope that is the only other issue.

Thanks

icegoffy

HI Koz, I am now getting the exact same symptoms, car bascially come to a frightening standstill after driving the the alerts lights on for about half an hour.

Am thinking of bringing it into dealer, but they quote me $700 just to take apart the aux tran pump to see what is going on. The pump motor itself cost 3grand.

Did you managed to fix your problem with bearing change?

KoSC300

Yeah, actually i did. I searched around for an aux transmission pump cooler, but no one sells it separate from the transmission because it has a wire loom and connectors attached to it. I ended up buying a used transmission for about $1350 and just swapped out the aux trans pump. The job was fairly easy to do as its only a couple of bolts, but you need to be able to refill the tranny fluid afterwards with a hand pump or something. After swapping it out, the car drives perfectly.

You'll first want to check if you're getting power to the oil pump controller that is located under the air box. Its the cheaper part to replace and pretty much tells the aux oil pump what to do. If its failing, the aux oil pump wont even run and the tranny fluid will begin to overheat with driving and lead you into limp mode. I purchased it initially and ended up not needing it. Let me know if you want mine for $300. It was only on my car for 15min as mine was working fine. If the controller is ok, then its likely the bearings. $700 is ridiculous as it is accessible from under the car, and held on by 4 bolts (one that is hard to reach) and attached to the wire loom.

Send me a PM with your location and contact info if you want to discuss it further.

icegoffy

Thanks for the quick reply

I am actually located in australia, so no-go
my symptoms was exactly the first scenario, it will come to a standstill, then i waited 5 mins and can drive again.

I wonder where did you get your controller from, is it from lexus themselves?

KoSC300

Ah... ok. The part i purchased is an OEM Lexus part i bought online. Cant remember the actual store, but if you read back on my older posts, part of my issue was that one of the wire connections on my car was messed up, and not the actual controller unit. While it was plugged in correctly, the contacts were not touching and no power was going to the controller. Thats why i said you should try to check if there's power going to the unit first. My mechanic had a Lexus buddy take a look and he just happened to bring an extra Lexus plug with him and replaced it. After that issue was fixed, my car drove fine without shutting down, but it would not go over 70mph still and the hybrid system would not engage. This was due to the bearing issue in the actual aux trans pump.

Not sure if you're confusing the two, but your issue likely having to do with the pump controller which is only in the $300-400 range for the part, as opposed to the actual pump, which is in the $3000-4000 range. Below is link to a pump online: http://www.lexuspartsnow.com/parts/l...167-30021.html

The pump controller is easy to get to and is located under the air box pipe. See below instructions on testing to make sure you're getting power to the pump controller first.

Remove the large connector from the Oil Pump Controller (mounted under the air box pipe). Get an Ohm-meter, and measure each of the three power wires on this connector, in turn, to ground (battery 0V); i.e. hold the black probe to battery 0V and the red probe to each wire in turn. Each winding will be about 0.5 ohms. If everything here checks out, your connections should be fine. Process of elimination, move onto purchasing the pump controller (G1167-30021). If the pump controller is ok, then the bearings in your pump may be seized entirely. Mine were'nt seized all the way, but they were going and the car sensed that it was not working efficiently and would limit me to 70mph.

icegoffy

Thanks mate, thats by far the best diagnostic details i have been given, very much appreciated

I am hoping for a lose connection somewhere, as i just replace the hybrid battery, but for 3 weeks after battery install it was working fine , only few days ago this problem occur

Is the lexus plug readily available? And if i change just the controller, do i need to replace the transmission liquid?

icegoffy

found out that there is power going to the controller, but not sure how to test whether the controller is working, it was definitely working few days ago. but i also notice the 12v battery went flat when we were testing the controller, now i am just thinking could that be the cause.

KoSC300

Below is a photo of a used controller i found online.
The controller is just a computer module that looks like a small ECU. So there is no transmission fluid to change. Its just 2-3 bolts and three electrical clips.

Yeah, you're definitely gonna want to make sure your battery is good before you move any forward. I just changed mine out for an Optima Yellow top two weeks ago because it would die randomly after sitting for a few days.

icegoffy

This is probably away from the topic, when u replace with optima is that the 12v battery you replacing? I read there is another battery which is high voltage and helps to cranks the engine

KoSC300

Yes, the optima is the 12V battery located in the trunk, driver side. I'm not entirely sure, but from what i know, the car doesnt have a starter, but uses the 12V battery power to start the car.