dytta

The following just happened with my 07 GS450h ( 40k miles) while driving on the motorway (in Norway) ;

- the engine fan started to operate during driving (outside temp -1 below).
- the yellow engine symbol came on
- then the traction control started to blink
- then the following messages :
* check hybrid system
* check VSC
* check DS.... something
* tire sensor failure lit up
- strange sounds coming from under the gearbox console
- engine started to rev, and car lost momentum
- most electrical systems started to fail (Navi, AC, info system etc).
- managed to get off the motorway and stopped after a couple of miles.
- car could by them only move forward with a speed of 4-5 miles per hour. slightest pressure on the gas pedal made the car rev up but not move.

I guess the chain of events and things that happened is part of the Lexus fail-safe system in order to prevent further damages ?

There is only one Lexus dealer in the whole country, but I managed to get the failure code read by a friendly Toyota dealer. It said P0A93 - Inverter Cooling system performance. They said that this looked like a similar problem that MANY Prius'es have. The pumps fails and causes the inverter to overheat. There is a recall for all Prius'es - free of charge in order to fix this problem.

Checked with Lexus in Norway. They said that this does not fall under the warranty, since the hybrid warranty only covers electrical parts. Sounds a bit strange since this cooling unit is an essential part of the hybrid system - and it is electrical.

Does anyone have experience with this ? There are only a few GS450's sold in Norway. Kind of expensive (USD 200.00), so there is little info to be found on the internet "over here".

Stormforge

Welcome to CL! I'm sorry to hear about your problems, this is the first time I've heard of P0A93 problem before. If your lexus service advisor doesn't provide a satisfactory resolution to your problem, go up to the next level and voice your concerns to the manager. If that doesn't work, take your complaint to Lexus Corporate.

I agree with your assessment that the P0A93 should be covered under warranty. Make sure you have plenty of documentation showing that Priuses gets this fixed under warranty, and that your GSh should be too.

Good luck and let us know how this goes.

dytta

Will know more tomorrow. Have now prepared a word document containing cut and paste of various related cooling/cooling pump problems - mostly for Prius'es. I could find very little on the GS model, except for a few cases of leakages in this particular system.
Info will follow.
Apart from this -I just love the GS Hybrid and have finally managed to break my chain of BMW and Audi's.

PJ82ND

check coolant at the water fill level on hybrid sys should b on driver side by firewall

The inverter converts the boosted high-voltage direct-current from the HV battery into alternating current for MG2 and MG1. The inverter generates heat during the conversion process, and this heat could damage the inverter if a cooling system is unavailable. Therefore, similar to MG2 and MG1, the inverter is cooled by a special cooling system consisting of an electric water pump, cooling fan, and radiator. This cooling system is independent of the engine cooling system. The hybrid vehicle control ECU monitors the electric water pump, cooling fan, and cooling system, and detects malfunctions

PJ82ND

i had the same problem on a gs450h was low on coolant for hybrid sys fill it up clear cel drove vehicle perform health check on techstream ck data list everything ok and followed up on vehicle n customer was satisfied with results .:-)

dytta

I picked up the car from the Toyota yesterday evening. The Lexus mechanic had found the electric cooling pump for the inverter to be defect. A new one was flown in from the main Lexus warehouse in Belgium and the old one replaced. The car now works as it should.
However, the guy who took in the car, told me that the coolant level was low.
They could not detect any leaks.
Due to this and the comment above, I will test the pump, to see it works or not. Low coolant level will probably cause the same chain of events that I experienced.
The job cost me USD 1400 (USD 400 for the work and USD 1000 for the pump) and even if the car has only 40k miles to it, there is no warranty.
I still have warranty on the hybrid system, but this electric system is not part of it. I will send a letter to Lexus centrally anyway and ask them to take the cost for the pump and that I pay for the work. This pump should not fail so soon, so maybe.....
Thanks for all your help. Will post a picture of the defect pump, so that you can see how it looks like.
Thorstein, Kristiansand, Norway

dytta

The cooling pump was replaced by Lexus (answer regarding warranty or not is still pending). 7 days after it was re-placed, it broke down again. The car has now been waiting for a new pump (delivery time 12 days).
The reason for yet another pump failure is unclear, but after examining it, I see that the electrical connector for the pump is not very well protected. The pump is placed low down in the enigine compartment. Maybe the connector should have a rubber cover/cap of some kind - just to protect it.
Maybe water and snow could have got to it and short-cut the thing. There was extreme weather in both failure cases.Maybe this could be the reason ?

bigblack06

iTrader: (20)

Man that sucks, seems as though its a constant problem, if the car is covered under warranty they should give you something for your problems since this is the second time!

LexFather

Thanks for the updates and good luck. Hybrid battery coolant levels should be checked by the dealer at major service intervals.

dytta

7 days after Toyota/Lexus replaced the hybrid coolant pump (for the second time in 5 weeks), I had another breakdown. Suddenly the car would not go faster than 45km/hour. It did so for a mile or so, then it came to a full stop, when the batteries ran out.
Back to Toyota, where they quickly found out that the crank shaft sensor had failed. When this happens, the main engine will close down and only elctric propulsion is possible.
They quickly replaced the sensor, but before they were able to give me the car back, the hybrid coolant pump broke down for the third time(during test drive).
After 2 months of continious troble, my local Toyota dealer have now contacted the technical department of Toyota Norway in order to get some serious help. What on earth can cause the hybrid coolant pumpt to break down three times during a few weeks ?

vap3

wow what a story, what happened? did lexus reimburse you? inverter coolant pumps usually fail on older priuses/highlander hybrids models, but a TSB was suppose to fix it with a new coolant pump. Didn't realize the problem trickled it way to the GS models... please update this thread with the conclusion! It will let me know if im going to buy a used gs 450h or not :O

RamAirRckt

Not sure if you're around anymore Dytta, but my GS450h is showing the issue. The first time in May 2021, I removed it and not having a new pump I verified if was freed up and reinstalled and it ran five for 7 months now stalled again. I suspect debris not a failed pump. I'm looking for a way to install a screen on the input of the pump.

Anyone else have issues and where were you able to find a pump?

GreekLex07

Good evening all,

Can someone post a pick of where the exact location is for the pump. Mine has failed and I'm not sure where it is.

Ok...I believe I have found it...It is underneath the car with some fins on it? Is this correct. Does anyone have a good source to purchase. I tried eBay but no luck.

Thank you

RamAirRckt

Down by the oil filter just to the drivers side (LHD).

Rap on it a few times and it might start working for a while. Debris is potentially an issue. I took my original one out and it spun free put it back in and it was fine for 7 months.

But ultimately it failed again and I replace it and hasn’t failed since. But when you replace it all the inverter coolant comes out so debris will come with it. There are no debris screens.

Black pump with a silver grey heat sink on the bottom. Follow the hoses from the inverter tank up top. You’ll find it. You can see from top but have to replace from bottom.

GreekLex07

@RamAirRckt Thanks Much...I will try that today and see if it helps. Did you have to bleed it? I will have to order one from the dealer as I cant find one used or on eBay if that doesn't work.