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GS450h excitement and horror


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Hello all, 

Bought this GS450H which has been nothing but exciting. I was so excited about the performance and the Lexus reliability that I decided to spend a bit of money to fix things like suspensions, completed a major service with Lexus etc The car still has full Lexus service history and 1 more service left with Lexus next year.

Few weeks ago, the CHECK ECB AND CHECK VSC lights came on which apparently was the ABS pump. I had this replaced and the lights were gone.

All of a sudden, I was sat in the car waiting for the Mrs to finish some shopping and left the car running for sometime listening to music. Switched off the car to help with shopping and on restarting, all thesame light came on (CHECK ECB AND CHECK VSC) but this time it came with the CHECK HYBRID SYSTEM. It went off by itself and all was fine.

A week later the lights just came on again but the car was behaving fine and driving with no issues. Yesterday, it miraculously only had the CHECK HYBRID LIGHT on with the VSC and ECB gone. Today, all lights off again.

Any advice on next steps would be highly appreciated. I've spent a little on the car as I was planning to keep it till it dies then get one of the last models. However, I am coming from a BMW and I have enough experience with money pits so very reluctant to spend more on especially if it's the beginning of the end.

Thank you

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If many errors appear at the same time you should first verify the 12V Battery as it could be at the end of its long life.

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As Luigi says, there's a very good chance that it's the 12V Battery on its way to Battery heaven.

These cars are so full of electronics that it can cause all sorts of weird and wonderful symptoms if the 12V Battery is dying.

I would suggest you go somewhere to have the Battery load tested. The chart below will give you some indication if you just check it against the Battery with a multimeter but if you then load it, that voltage could drop like a stone if a cell's gone bad. If you then check with the car in READY mode it should read about 14.5V if the charging circuits are working alright.

If all that proves to be OK, then as Colin says, you need to get the OBD2 codes or it's all just guesswork.

EDIT - forgot to upload the voltage chart :wallbash:


1525684991_batterycharge.thumb.jpg.4d6e2b470d5ed722f8f5eeb556e3b08b.jpg

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Agree, when my 12 volt battery was beginning to pack up I was getting all kinds of error messages on start up

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Thank you all, I have just started the car and there was no check VSC, ECB or HYBRID SYSTEM light on. The only light on is a small yellowish amber engine management light. I also just connected an OBDII fault reader. There were 3 faults in total with one pending. I have left the codes on and did not delete them. Any clues would be helpful

P0420

P0430

P0420 (Pending)

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I would check 12V Battery and see what is voltage over time, when the 12V Battery playing up it affect rest of the system and when it affect engine e.g. running rough it dump fuel into exhaust and cause sensor to pick up error at the cat. When the 12V Battery on its way out it does not hold charge and when you managed to start the car it charge it up and symptoms goes away until next time when you start up and it drop below the working voltage to run thee computer management system properly  

Or it could be something completely different as I am not a mechanic just another Lexus lover who had a 12V problem before 😛 

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2 hours ago, Gentleman said:

Thank you all, I have just started the car and there was no check VSC, ECB or HYBRID SYSTEM light on. The only light on is a small yellowish amber engine management light. I also just connected an OBDII fault reader. There were 3 faults in total with one pending. I have left the codes on and did not delete them. Any clues would be helpful

P0420

P0430

P0420 (Pending)

P0420 17 Catalyst System Efficiency Below Threshold (Bank 1) - With Engine Warm & Driven at 20-50 MPH for 5 Minutes, Heated Oxygen Sensors Have Same Wave Patterns (Cam.)

P0430 Catalyst System Efficiency Below Threshold (Bank 2)

Needed more investigation... 

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  • 2 weeks later...

UPDATE:

Just wanted to thank you all. I took the car to the garage and I have been informed that the catalytic converter is blocked. The gentleman rang me earlier today that he can get a used one for around £550 from a reliable garage where they break down GS450s but it may take a few weeks for it to arrive. 

 

I was reassured that it is safe to drive and I'll be called once it has arrived. I will use this opportunity to drive it and see if the multiple error codes come up again. So far nothing yet. I will keep the group upated.

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On 8/3/2021 at 9:05 AM, b4u2 said:

What does that mean? 

It means air cannot efficiently pass through the cat because the honeycomb is blocked up, either by carbon deposits or because pieces of the catalytic material have broken off and blocked it.

It isn't something that is common on Lexus vehicles, especially if the engine is running correctly.

The IS200 could suffer from this but normally only when fitted with a supercharger which raised the exhaust gas temperatures, damaging the cat and causing it to break up.

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On 8/3/2021 at 9:05 AM, b4u2 said:

What does that mean? 

Honestly, I don't know what it means apart from the literal interpretation that it is blocked. The car still works and no further random flashing of lights apart from the engine management light. 

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6 minutes ago, ColinBarber said:

It means air cannot efficiently pass through the cat because the honeycomb is blocked up, either by carbon deposits or because pieces of the catalytic material have broken off and blocked it.

It isn't something that is common on Lexus vehicles, especially if the engine is running correctly.

The IS200 could suffer from this but normally only when fitted with a supercharger which raised the exhaust gas temperatures, damaging the cat and causing it to break up.

Thanks for this explanation. By the way, is replacement the next step or can this be cleaned?

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12 minutes ago, Gentleman said:

Thanks for this explanation. By the way, is replacement the next step or can this be cleaned?

If it is actually blocked then typically you would need to replace it - certainly that is the case if it has broken down, or parts of it damaged by unburnt fuel, igniting in the cat and melting it.

Proper confirmation needs a camera inserted into the exhaust to look at the honeycomb, or the cat removed and inspected, to confirm. You would also want to make sure the reason why it failed is understood and resolved.

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1 hour ago, ColinBarber said:

You would also want to make sure the reason why it failed is understood and resolved.

I just want to emphasize this.

A cat either gets poisoned, or gets physically damaged - melted, broken down, etc.

Poison primarily comes from certain components in motor oil - the oil's SAPS (low/mid/high) rating generally tells you how "safe" it is for converters - if the particular components end up burning through the combustion chamber. Coolant and leaded fuel also poison cats.

Destruction can happen in many ways. Misfires or bad combustion get unburned fuel into the cats, igniting it there and causing pressure damage. A rich mixture typically cools cats down, unless it's caused by an air leak in the exhaust system before or near the air/fuel sensors - then it can heat them up rapidly. A lean mixture generally causes cats (and engine components near the combustion chamber - pistons, valves) to overheat, melt and so on.

Make absolutely sure that there are no exhaust leaks before or anywhere near the (front and rear) O2 sensors. This is usually checked with a smoke machine. This generation of GS's typically have pinhole leaks after the secondary O2s and before the secondary cats - right underneath the shielded section of the exhaust pipes there.

Make sure that the O2s work. The upstream ones are wideband (AFR), the downstream ones are the regular type. The car can be told (via techstream or anything else that offers similar utility) to run rich (up to +25% fueling) or lean (up to -12.5%) to confirm proper operation of the O2 sensors.

 

If you decide to go for new OEM units, as getting good aftermarket cats appears to be a problem, make sure that you've resolved any such issues. In summary - fix any kind of oil/coolant loss, make sure that there are no intake or exhaust leaks, make sure that the O2s work properly. Might wanna replace the primary O2s regardless.

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9 hours ago, Lwerewolf said:

I just want to emphasize this.

A cat either gets poisoned, or gets physically damaged - melted, broken down, etc.

Poison primarily comes from certain components in motor oil - the oil's SAPS (low/mid/high) rating generally tells you how "safe" it is for converters - if the particular components end up burning through the combustion chamber. Coolant and leaded fuel also poison cats.

Destruction can happen in many ways. Misfires or bad combustion get unburned fuel into the cats, igniting it there and causing pressure damage. A rich mixture typically cools cats down, unless it's caused by an air leak in the exhaust system before or near the air/fuel sensors - then it can heat them up rapidly. A lean mixture generally causes cats (and engine components near the combustion chamber - pistons, valves) to overheat, melt and so on.

Make absolutely sure that there are no exhaust leaks before or anywhere near the (front and rear) O2 sensors. This is usually checked with a smoke machine. This generation of GS's typically have pinhole leaks after the secondary O2s and before the secondary cats - right underneath the shielded section of the exhaust pipes there.

Make sure that the O2s work. The upstream ones are wideband (AFR), the downstream ones are the regular type. The car can be told (via techstream or anything else that offers similar utility) to run rich (up to +25% fueling) or lean (up to -12.5%) to confirm proper operation of the O2 sensors.

 

If you decide to go for new OEM units, as getting good aftermarket cats appears to be a problem, make sure that you've resolved any such issues. In summary - fix any kind of oil/coolant loss, make sure that there are no intake or exhaust leaks, make sure that the O2s work properly. Might wanna replace the primary O2s regardless.

Great explanation Alex, thanks, in your experience might processes such as Terraclean resolve an issue? 

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  • 1 month later...

I am attaching some pictures to visualise the issue but the key thing was to say thanks to all of you that responded. It took a while but I think it is now sorted. I have had the cats replaced and the warning lights are gone. Thank you all for your help and suggestions. Also, the car feels quieter as well, although this may be a placebo effect.

 

 

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