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Hybrid TechnologyUnique topics related to the GS450H model hybrid drivetrain and other features/options found only on the GS450H. Please use the main 4GS forum for discussion about shared components with other fourth generation GS models.
Sorry to hear about the all trouble you're facing with your relatively "new" car (in terms of mileage) @Hues10 . I just wanted to thank you for continuously responding and updating the community. I know it sucks having to go through things for the first time, but I guarantee this topic will be extremely valuable in the future, especially if you can provide more details (OBDII DTC codes, what the source of the problem is, etc).
Your 12V battery reading seems fine; I would also considered that the culprit if you didn't just replace it 3 years ago. It has to be something else!
I hope it's something minor because I highly doubt the main hybrid batteries are dying out that early. I've read about 3rd Gen folks going 200K+ miles with no issues.
@Hues10 - Just wondering - did you ever have your fuel pump replaced under the Lexus Special Service Campaign 21LC01?
Maybe something like a failing fuel pump, which is a peripheral component and not directly part of the hybrid system is the cause of triggering the Check Hybrid System message. The ICE and hybrid system are interconnected and count on each other for power and charging the traction battery. So, it could make sense that an ECU's design parameters could include something like a failing fuel pump and trigger such a Check Hybrid System message...
Just thinking/searching for a cause of the 'Check Hybrid System' message and blank hybrid energy flow graphic you received beyond what little we know so far!
The Lexus Special Service Campaign 21LC01 (Remedy Notice) states that multiple models and model years may experience low pressure from the fuel pump causing the engine to run rough, or for the fuel pump to stop working. The remedy is to replace the fuel pump with an improved unit at no charge.
The Lexus Special Service Campaign 21LC01 Remedy Notice is in the attachment of this post.
Last edited by bclexus; 07-26-24 at 03:14 PM.
Reason: orthography
Thanks everyone for your input. Here is the update. Charged up the 12V battery today to 12.8 from the 12.19. Started car, Check Hybrid Message still on, no graphics. Then after about a minute, the car engine shuts off. I think it has stalled or something. And I am like, oh crap, this is it. Tow job to Lexus. For whatever reason, I decide to restart it, which it does, and I figure, what the heck, shift into drive and go up the driveway. Now I have a very long driveway, so if it stalled out, no problem, I am still at home. Well after 10 feet in Drive, the graphics kick on showing everything like normal. The engine, the EV motor, and the Battery. All getting their little sources of power flowing. What the heck, let’s go for a drive. so I ended up doing a 5 mile loop, with the everything seemingly normal, except the Check Hybrid Message is still on. So I plan on driving it tomorrow for golf (5 miles one way), and then back home, just to see what happens. The scanner is supposed to come Sunday, so I will hook it up and read the codes to see what it is saying. Then I will try to reset it if I can and report back. I am hoping the error message goes out on its own. Not out of the woods yet, and the multimeter is in the trunk right now. Though I like the cigarette lighter thing as well. If it is accurate. If you are still awake after reading, thanks again.
For whatever reason, I decide to restart it, which it does, and I figure, what the heck, shift into drive and go up the driveway. Now I have a very long driveway, so if it stalled out, no problem, I am still at home. Well after 10 feet in Drive, the graphics kick on showing everything like normal. The engine, the EV motor, and the Battery. All getting their little sources of power flowing. What the heck, let’s go for a drive. so I ended up doing a 5 mile loop, with the everything seemingly normal, except the Check Hybrid Message is still on. So I plan on driving it tomorrow for golf (5 miles one way), and then back home, just to see what happens. The scanner is supposed to come Sunday, so I will hook it up and read the codes to see what it is saying. Then I will try to reset it if I can and report back. I am hoping the error message goes out on its own. Not out of the woods yet, and the multimeter is in the trunk right now. Though I like the cigarette lighter thing as well. If it is accurate. If you are still awake after reading, thanks again.
Oh, you daredevil you - driving it to the golf course!
I knew we were bonded somehow! I played tournament golf for a number of years.
................
Thanks everyone for your input. Here is the update. Charged up the 12V battery today to 12.8 from the 12.19. Started car, Check Hybrid Message still on, no graphics. Then after about a minute, the car engine shuts off. I think it has stalled or something. And I am like, oh crap, this is it. Tow job to Lexus. For whatever reason, I decide to restart it, which it does, and I figure, what the heck, shift into drive and go up the driveway.... Well after 10 feet in Drive, the graphics kick on showing everything like normal. The engine, the EV motor, and the Battery. All getting their little sources of power flowing.What the heck, let’s go for a drive. so I ended up doing a 5 mile loop, with the everything seemingly normal, except the Check Hybrid Message is still on.So I plan on driving it tomorrow for golf (5 miles one way), and then back home, just to see what happens. The scanner is supposed to come Sunday, so I will hook it up and read the codes to see what it is saying. Then I will try to reset it if I can and report back. I am hoping the error message goes out on its own. Not out of the woods yet, and the multimeter is in the trunk right now. Though I like the cigarette lighter thing as well. If it is accurate. If you are still awake after reading, thanks again.
@Hues10 - With the results bolded in green I'm betting whatever triggered the 'Check Hybrid System' message is on the minor side and hopefully an easy and inexpensive fix.
If you are able to make it back from playing golf (after shooting a personal low gross round and emptying your playing partner's wallets) you can expect to successfully drive the car 45 miles to your Lexus dealer for a proper diagnosis and repair - - and maybe they'll give you a brand new LC500 loaner to test drive back home!
I think a key bit of information you revealed is that the car engine shut off on your first try to start the car in your attempt to learn how it would respond. I think the reason the engine shut off happened is central in finding the root cause of the 'Check Hybrid System' message and the resulting lack of energy flow graphics you experienced early-on...
Last edited by bclexus; 07-26-24 at 07:04 PM.
Reason: orthography
I like the cigarette lighter thing as well. If it is accurate.
Did you say; 'if' it is accurate'? It's pretty accurate!
The 'cigarette lighter thing' (as you call it) has a rated accuracy of 2.5% which provides a reading within 0.5 volt for a fully charged or actively charging battery of ~13 to 14 volts, but it's probably even more accurate than the 2.5% accuracy rating.
I may test it with my Fluke High Accuracy True-RMS Digital Multimeter (that has a DC Voltage accuracy rating of 0.5% to 0.025%) just to see how accurate the cigarette lighter thing's integral IC chip really is!
Also, with you being a golfer you might own something like a SkyCaddie SX400 - which has a battery that can be conveniently charged using one of the dual Quick Charger 3.0 USB ports, each rated at 24 watt / 4.8 ampere.
Look at the video below for a perspective of the Palumma Dual USB Charger's voltmeter accuracy...
I'm leaning toward the problem being more associated with the ICE in regard that the hybrid system is almost entirely dependent on the ICE (with the exception of the regenerative brakes) to provide and maintain energy to and for the traction battery. Thus, if something is amiss with anything on the ICE whereby it cannot provide energy for the hybrid system, then it's reasonable to suggest the hybrid system's ECU will display the 'Check Hybrid System' message... Maybe!
This is why I'm asked you about your car's fuel pump - because the fuel pump that Lexus wants replaced is known to operate (pump) intermittently and can stop working on occasion. Depending on driving circumstances the driver of a hybrid might not even be aware when the fuel pump unexpectedly stops working on occasion, which might trigger the hybrid ECU to display the 'Check Hybrid System' message.
As I posted previously: I think a key bit of information you have revealed is that the car engine shut off on your first try to start the car in your attempt to learn how it would respond. I think the reason the engine shut off is central in finding the root cause of the 'Check Hybrid System' message and the resulting lack of energy flow graphics you experienced early-on...
Last edited by bclexus; 07-27-24 at 07:36 AM.
Reason: orthography
I like the cigarette lighter thing as well. If it is accurate.
I just received the Palumma Dual USB Charger with Voltmeter & Ammeter
I tested the Palumma Dual USB Charger with Voltmeter & Ammeter on my 2018 GS 450h that had not been driven for over 12 hours.
Here's my voltage readout results:
► One Push on Start button for Accessory Mode to power up the car:
Mark Levison sound system On, driver's door open with interior dome light, floor lights and door sill light On:
Voltage: 11.8 Volts (With significant load on standing battery)
► Engine started with all the above electrical loads still On plus the headlights On:
Voltage: 13.9 Volts (climbed to 14.5 Volts after ~ 30 seconds)
I checked the standing battery voltage again in Accessory Mode a few minutes after the engine was Off with above noted loads still On (less headlights):
Voltage: 12.8 Volts - 12.6 Volts
Note: Voltmeter Accuracy is ±1%: Voltmeter reading 12.7 Volts - Fluke High Accuracy (DCV 0.5% to 0.025%) reading: 12.584 Volts = ~ 0.12 Volts = ~1%)
Last edited by bclexus; 07-28-24 at 05:55 AM.
Reason: orthography
Just a quick reply, car ran to/from golf course - 10 mile round trip. No issues, except the Check Hybrid Message still active. Waiting on Amazon to try and scan for codes and hopefully reset. And if you care, and even if you don’t, shot a 42 on a course I have never played, and have not played a round in 10 months. Well above, in this case below, my expectations of my score. And getting an LC500 loaner would be sweet! Right now I am not in dire emergency mode to get car to Lexus. Yet that is.
I guess I need to either get TechStream, or get the car to a Lexus dealer to do a proper scan. Here is what I show with the $60 Amazon scanner I bought. I guess it is good news to not find anything related to anything else other than the Check Hybrid System error message.
07-26-24, 09:58 AM
I played tournament golf for a number of years.
It's pretty accurate! 
