Problems when doing a long trip

[Stephen123]

Good day, I bought a GS450h 18 months ago and just love driving it, lovely car. I live in Whitianga which is a small town in New Zealand and to go anywhere of some distance one needs to cover 1 hour of hilly and winding road. While I drive the car around town here, there is no problem at all, everything is great. However, since owning the car ( its a Japanese import ) when I drive over the hills, eventually the red triangle light comes on, and sometimes the yellow engine block light comes on.

Also on a few occasions I have found that after completing a trip of 2-3 hours, when I try to restart the car it wont start unless I keep pushing the start button when the engine will kick in, if I try to put it in gear straight away it will stop but if I wait 30 seconds or so I can get it into gear and drive it but the hybrid electrics will not kick in, engine will stay running, and red triangle and engine block lights stay on. After using the car a couple of times, the warning lights still on but everything else running fine, the lights will then disappear and all will be fine until the next long trip I do. Its weird and a bit inconsistent. I have taken it to Lexus 4 times, and they originally diagnosed the problem as transmission pump and controller error so I had both of these replaced with new parts. This still didnt fix the problem and they have tried various other tests over time, including replacing the Battery in the boot, 12 volt, still no better. It seems the problem may be related to heat driving the car over a longer distance however Lexus are still baffled as to the real issue. If anyone has experienced something similar, or has any ideas, please let me know, I would be very grateful. Cheers, Steve

[royoftherovers]

8 hours ago, Stephen123 said:

Good day, I bought a GS450h 18 months ago and just love driving it, lovely car. I live in Whitianga which is a small town in New Zealand and to go anywhere of some distance one needs to cover 1 hour of hilly and winding road. While I drive the car around town here, there is no problem at all, everything is great. However, since owning the car ( its a Japanese import ) when I drive over the hills, eventually the red triangle light comes on, and sometimes the yellow engine block light comes on.

Also on a few occasions I have found that after completing a trip of 2-3 hours, when I try to restart the car it wont start unless I keep pushing the start button when the engine will kick in, if I try to put it in gear straight away it will stop but if I wait 30 seconds or so I can get it into gear and drive it but the hybrid electrics will not kick in, engine will stay running, and red triangle and engine block lights stay on. After using the car a couple of times, the warning lights still on but everything else running fine, the lights will then disappear and all will be fine until the next long trip I do. Its weird and a bit inconsistent. I have taken it to Lexus 4 times, and they originally diagnosed the problem as transmission pump and controller error so I had both of these replaced with new parts. This still didnt fix the problem and they have tried various other tests over time, including replacing the battery in the boot, 12 volt, still no better. It seems the problem may be related to heat driving the car over a longer distance however Lexus are still baffled as to the real issue. If anyone has experienced something similar, or has any ideas, please let me know, I would be very grateful. Cheers, Steve

Hi Steve, I have same car,but not had the problems you have described.

Why don`t you ask on the USA site as they sell a lot of 450h over there ?

[johnatg]

Welcome to the forum, Steve.

Throwing parts at this is going to be very expensive - you really need proper diagnosis. Are any fault codes registered? They should be stored, even if things seem to have reverted to normal. You should be able to purchase a low cost fault code reader (connecting to the OBD11 port) which will show faults on your smart phone.  Be careful with interpretation of fault codes though - often the actual fault may not be what the code first indicates.

The symptoms point to a sensor failing - they often fail gradually, starting only when they get hot and then eventually causing problems at lower and lower temperatures. Maybe the camshaft or crankshaft position sensors. The oil control valve is another possibility. Problems with these things may only show up under failure conditions and you may need to have an oscilloscope used to analyse the signals. I appreciate that may be difficult in your location and even more so if you are on a long trip.

Get back to us if you can identify any fault codes. Good luck!

[Stephen123]

Thanks for your advice John, I will pass this on to Lexus and they can follow up when the car is back there again

[Stephen123]

On 1/23/2023 at 9:25 PM, royoftherovers said:

Hi Steve, I have same car,but not had the problems you have described.

Why don`t you ask on the USA site as they sell a lot of 450h over there ?

Thanks, I will

[Stephen123]

On 1/25/2023 at 9:55 AM, Stephen123 said:

Thanks, I will

 

On 1/25/2023 at 9:43 AM, Stephen123 said:

Thanks for your advice John, I will pass this on to Lexus and they can follow up when the car is back there again

 

On 1/25/2023 at 9:43 AM, Stephen123 said:

Thanks for your advice John, I will pass this on to Lexus and they can follow up when the car is back there again

Hi John, Further to your comments re sensors, would a faulty sensor result in the car taking several tries to start after a long trip, thanks

[NemesisUK]

If the engine is still warm the CPS could be failing, causing failure to restart 

[johnatg]

A vital sensor such as the crankshaft position sensor, could easily be downgraded for some time after the heat event.

But, really, I can't tell from here. You need skilled hands on diagnosis.

[Stephen123]

Thanks a lot John