GS450h Hot Start Problem

[AshGS450h]

Hi

I have an issue where the car drives and runs fine from cold, but once the engine is up to temperature, pull up at a set of lights and the engine switches off (all normal so far). When setting back off the engine starts for about 3-5 seconds and then shuts off without delivering any power. The check engine light comes on and the display shows Check Hybrid System.

I pulled over and turned the car off, left it a minute and restarted it and the engine did the same again. I left the car for 90 mins and went back to it (only round the corner from my house luckily), and it fired up as normal and drove fine, power, response, etc, all normal until I drove it about 1.5 miles and the same again.

I left it a further 2 hours and it worked fine again but I didn’t drive it to “fail” again but it drove fine the 0.5 miles back home and charged the Battery 2 bars back to 6.

I managed to ready the codes and the generic reader only read P3191. Reading this it looks like it’s reasonably obvious that it’s going to be a crank sensor, cam sensor, MAF or throttle body.

The throttle body was cleaned just under 12 months ago but the others are untouched.

Does anyone have any experience of which of the three are most likely place to start? I’m hoping MAF because I can imagine the others are buried under many other items 😞

Thanks in advance for any suggestions

 

Ash

Car: 2007 GS450h, 134k, new traction Battery at 124k and full service history (Lexus up until 2017, then Local Indy 2018-> but using all genuine parts/oil/etc).

[Britprius]

Hi Ash. The code you give is for "engine did not start". So my question must be are you sure it does start as when the engine is spinning on it's electric motor (MG!)? it will sound as if it's running. The ECU will allow it to spin for 5 seconds, and then aborts the starting attempt. The ECU also limits the number of start attempts to prevent the HV Battery from being depleted. If this happens it's a dealer job to recharge it "unless your reasonably skilled at building a 330 volt Dc constant current charger".
Get the Battery to as high a state of charge as you can by starting the car leaving it in park, with the heater fan turned on, and controls set to hot. This should charge the Battery to a safe level.
You then need to investigate why it is not starting. I suggest you buy Techstream to read all the codes as there must be more. You could try cleaning the crank sensor, but without codes life could be difficult. Whatever you do do not let the HV Battery get to low on charge.

John.

[steve2006]

Obviously diagnostics are always the first move but the most common part to fail thermally on any modern car is the crank sensor.

If you can gain access to it a good test to confirm thermal breakdown is to spray it with “freezer spray.” ( eBay is a source or RS components)

When the fault appears cool the sensor down with the spray, if the engine then starts and runs normally the sensor is the problem.

If you want to do the testing on the driveway use a hairdryer to heat the sensor and see if the fault appears, then use the freezer to see if the fault rectifies.

Notice you are in Derbyshire...if you want some spray or even want me to take a look I’m near Alfreton.

[Troy Tempest]

Hi Ashley

I wish I had something helpful to add or advise, but I don’t ☹️

This sounds very familiar to me though; I had a couple of broadly similar experiences during the hottest days of last summer.  I took mine to the dealership and they said my Battery was on its last legs and needed replacing ☹️
 

Good luck getting it sorted!

Si

[AshGS450h]

Hi All

Thanks for the reply’s and pointers on where to look.

I have had the car into an Indy mechanic and on his fault code reader he got P0017 I think. Something about Crank and Cam sensor mismatch and the timing not being as expected. As it was due an oil change/intermediate (using genuine Lexus/Toyota parts & 0w20 oil) service he’s done that as he says the oil can sometimes be the issue with it breaking down over time and not allowing the VVTi work correctly???

But it has again not started when the engine is warm and the ambient temperature was on 18deg today 😕

He did say that the crank sensor could be reasonably easy to change and if the service didn’t cure it, then this would be his next idea.

Just wondering if anyone has any pointers from the P0017 code?

Thanks again

[Britprius]

1 hour ago, AshGS450h said:

Hi All

Thanks for the reply’s and pointers on where to look.

I have had the car into an Indy mechanic and on his fault code reader he got P0017 I think. Something about Crank and Cam sensor mismatch and the timing not being as expected. As it was due an oil change/intermediate (using genuine Lexus/Toyota parts & 0w20 oil) service he’s done that as he says the oil can sometimes be the issue with it breaking down over time and not allowing the VVTi work correctly???

But it has again not started when the engine is warm and the ambient temperature was on 18deg today 😕

He did say that the crank sensor could be reasonably easy to change and if the service didn’t cure it, then this would be his next idea.

Just wondering if anyone has any pointers from the P0017 code?

Thanks again

P0017 is often caused by a stretched timing chain.
It gives the code for bank 1 cam sensor "passengers side bank" compared to the crank position. This is because the length of chain being pulled round by the crank goes from the crank to bank 2 then down to the idler sprocket above the crank, and then back up to the bank 1 timing sprocket where the sensor is located.
When the chain is stretched it causes bank 1 cams to be retarded, and in severe cases can cause the chain to jump teeth on the sprocket.

John.

[Britprius]

This may help.

 

 

John.

[AshGS450h]

Hi John

Thanks for the insight. I wouldn't have thought a chain could stretch enough on a car with "only" 134k on the clock. The previous BMW 330d had over 230k on it and that hadn't had an easy life and not a single issue with the chain and looked like new when inspected!

Probably a daft question but is it a massive job to do this or reasonable?

Also, is access not too bad or will it take the mechanic a long time to do? Are special tools required?

Just wanting to have a bit of insight into the job rather than going in blind to the garage.

Thanks again

Ash

[Mihanicos]

Hi,

Make sure that the 12v Battery is in a good state of charge and that the voltage does not fall below 11v. Measure the voltage when the car fails to start and you get unrelated electrical faults and codes.

I had a similar case with a Lexus and the symptoms point to the Top Dead Centre position sensor. Look at the freeze frame data to verify the events prior to the display of the code.

Another item to look at are the oil filters feeding the intake camshafts with oil in order to vary their timing with respect to the crankshaft position. Sometimes they get clocked up and the variable timing feature of the engine is impeded. Make sure you use the right viscosity engine oil, although it would have to be a very different oil viscosity to cause a DTC display.

 

Chris.

 

[Farqui]

Hi Ashley,

As Chris mentions, I'd check each of the cam oil feed filters (one per bank) which shouldn't take too long. 

I did find getting the NS one out what quite tricky as there isn't much clearance.  So maybe start on the OS and see what condition that one is in before deciding if it's worth checking the other.  Mine were both spotless at 130k.

Good luck and keep us posted.

Cheers, Lee

[J88TEO]

3 hours ago, Farqui said:

Hi Ashley,

As Chris mentions, I'd check each of the cam oil feed filters (one per bank) which shouldn't take too long. 

I did find getting the NS one out what quite tricky as there isn't much clearance.  So maybe start on the OS and see what condition that one is in before deciding if it's worth checking the other.  Mine were both spotless at 130k.

Good luck and keep us posted.

Cheers, Lee

Hi Lee,

Interesting! I haven't checked mine.

BTW, where are these filters located?

Cheers.

Joe

 

[Farqui]

Joe, they are both at the front of the engine on the outside of each cylinder head. Locate the vvt solenoids and work out/down to the hard oil feed pipe with a large center bolt. This bolt is hollow and houses a filter.

More info here (for an RX but gives you an idea) https://www.clublexus.com/forums/rx-1st-gen-1999-2003/662865-vvt-solenoid-ocv-replacement-diy.html#post7575578

[Farqui]

https://lexus.7zap.com/en/jp/lexus+gs/334110/gws191-bexqh/1/1104/114128g/#15678E

[Farqui]

[Britprius]

4 hours ago, AshGS450h said:

Hi John

Thanks for the insight. I wouldn't have thought a chain could stretch enough on a car with "only" 134k on the clock. The previous BMW 330d had over 230k on it and that hadn't had an easy life and not a single issue with the chain and looked like new when inspected!

Probably a daft question but is it a massive job to do this or reasonable?

Also, is access not too bad or will it take the mechanic a long time to do? Are special tools required?

Just wanting to have a bit of insight into the job rather than going in blind to the garage.

Thanks again

Ash

I am not saying that your chain has failed, but it is a possibility. So check the other avenues first.
There have been reports of this problem on the Toyota V6 engines at only 100,000 miles. The chain is only a single row chain driving 4 cams "two indirectly", and is quite long. It only takes a thousands of an inch in each link to give enough extra length to cause problems. I believe on later engines they fitted a duplex chain.
I have replaced chains on V6 & V8 engines without dismantling the front of the engine saving hours of work. Do a search on Youtube on changing the timing chain they are quite informative. The downside of using "my" method of changing the chain is that it does not replace the timing chain tensioner guides just the chain. Having said that I have not had any failures after just changing the chain.
If you require more information let me know, and I will see what I can dig out.

John

[Britprius]

16 hours ago, Britprius said:

P0017 is often caused by a stretched timing chain.
It gives the code for bank 1 cam sensor "passengers side bank" compared to the crank position. This is because the length of chain being pulled round by the crank goes from the crank to bank 2 then down to the idler sprocket above the crank, and then back up to the bank 1 timing sprocket where the sensor is located.
When the chain is stretched it causes bank 1 cams to be retarded, and in severe cases can cause the chain to jump teeth on the sprocket.

John.

I made a mistake in my description above the wording should read bank 1 cam sensor drivers side.

John.

[Britprius]

Look at the video below starting at 34 minutes in. This will show how the stretch in the chain affects the cam timing, and how it affects the tensioner. This is for a 4ltr engine but is otherwise identical.
There is an inspection cover in front of the tensioner that can be removed to see how far it has extended giving an idea of how much stretch there is. without dismantling the engine

 

 

John.

[steve2006]

Please don’t tell me we are now going to suffer the very same problem from decades ago when chain stretch resulted in manufacturers moving to belts! You would have thought by now technology would have improved enough to produce a non stretch chain and reliable tensioners.

[J88TEO]

7 hours ago, Farqui said:

https://lexus.7zap.com/en/jp/lexus+gs/334110/gws191-bexqh/1/1104/114128g/#15678E

Lee,

Great. Thanks.

Alternator coming out tomorrow so will look into these also.

Cheers.

[Britprius]

1 hour ago, steve2006 said:

Please don’t tell me we are now going to suffer the very same problem from decades ago when chain stretch resulted in manufacturers moving to belts! You would have thought by now technology would have improved enough to produce a non stretch chain and reliable tensioners.

Steve although we call it chain stretch it is actually ware on each link pin, and link that gives the phenomena. The longer the chain the greater the effect If you watch the video "Episode 5" at about the 45 minute mark you will see the chain elongation against a new chain is only about 1/3". This on a chain of about 350 link pins equating to less than 1 thou per link pin in ware.
The chain is still otherwise perfectly usable.
The problem is in the design of the cam position monitoring being so precise that on the longest run of loaded chain driving the cam the system throws an error for the cam timing being 1/2 a tooth out. This is not enough to cause running problems on it's own. It is the error code that causes the problem.

I would prefer a chain to a belt every time. It is perfectly possible to change the chain without dismantling the front of the engine as in the video, quicker than changing a belt. It is also less likely to break causing catastrophic engine damage. 

John.