Got another GS450h. It's a bit poorly.

hazelnut · August 23, 2023

I couldn't resist buying another GS450h from auction. My first one required a replacement inverter, and I have spare inverter just in case.

The new one is a lovely silver-blue colour, and was delivered with a dead 12v Battery and two flat tyres (it was a bargain). I've fitted a charged 12V Battery, and checked the oil level of the engine, then checked the engine turns over by hand. Got in, pressed START, and the engine ran for about 2 seconds. I got the computer out, and I have the following DTCS:

   P0A80 Replace Hybrid Battery pack
   C1259 HV/EV Control System Regenerative Malfunction
   C1310 HV/EV System Malfunction

I saved the data in Techstream, cleared and went for a retry, but no engine start this time, READY only flashes for a fraction of a second. Back indoors I opened up the Techstream file, expecting to see all the freeze frame data and Battery voltages, but they are not there !

Now I guess the HV Battery could be dead, but then again it might be the inverter not charging the Battery? Other than just swapping working bits over has anyone come across this set of DTCs before?

Image attached for your entertainments.

PS added some screen photos of Techstream showing Battery cell voltages. The Hybrid Control ECU doesn't think there is anything wrong with the regen, so I guess I need to remove the Battery ? Or figure out a way to charge it up...

Edited August 23, 2023 by hazelnut
more pictures

Steven Lockey · August 24, 2023

Codes are generic enough that it could be anything.

Fact it started means there is some voltage in the traction Battery and they don't look like dead
Battery codes. But that leaves a lot of things it could be.

The 2nd code makes me suspicious that it might be something to do with the electric engine
or gearset, since that implies reduced electric motor output.

The ECU itself is apparently sometimes the culprit:
https://www.lexunx.com/hv_control_system_regenerative_malfunction_c1259_c1310_-766.html

hazelnut · August 25, 2023

7 hours ago, Steven Lockey said:

The ECU itself is apparently sometimes the culprit:
https://www.lexunx.com/hv_control_system_regenerative_malfunction_c1259_c1310_-766.html

Thanks for this, that looks like a good resource, better than paying £7 / hour to use the Lexus on-line manuals. So it seems the C1259 and C1310 errors are from ABS ECU whenever it gets an error from the Hybrid ECU, so as I suspected they are secondary DTCs. The primary one being the POA80 error. So looks like I will be pulling the hybrid pack, rebalancing it, and putting it back in.

Steven Lockey · August 25, 2023

Don't think its on any error as when my Battery was dying, it didn't display this error.
Possibly that Battery is even more dead which produces the extra codes.

If it was the Battery through, it normally also gives you a secondary error with which cell pack it is.

hazelnut · August 27, 2023

I pulled the Battery and tried to see if the weakest cell would take any charge using a lab PSU. There is quite a bit of corrosion on the module bus bars, but it does not seem to affect the module=module resistance. I've found this bit of kit which may save me some time. It is called a C1-XR. There is a 4 channel version that plenty of Lexus/Toyota repairers claim to use. I found someone selling them in the UK, so I've ordered one, and if it works out I may buy a few more.

hazelnut · September 7, 2023

Finally put the rebuilt Battery in today on the hotest day of the year so far. Took some Battery voltage readings on Techstream, then went for a "start". The engine ran for a couple of seconds, then stopped. I now have two new DTC in the Engine ECU:

P0335 Crankshaft Position Sensor "A" Circuit
P0345 Camshaft Position Sensor "A" Circuit

hazelnut · September 8, 2023

One advantage to having two GS450h, is parts swapping. The N/S Cam sensor works just fine in the running GS450h. This makes me think there is either a wiring issue or an Engine ECU problem. I guess I will try to get the crank sensor out by loosening the A/C compressor.

hazelnut · September 10, 2023

I managed to get the crank sensor out, and it appears ok with a resistance of 2.159 kOhms. It is just about possible to remove the sensor by loosening the AC compressor's two bolts and one nut. The thing that slowed me down was removing the ECUs as the nuts to the brackets were totally rotten and very difficult to remove.

hazelnut · September 10, 2023

Sadly the NX website isn't that good for ECU troubleshooting, as the ECU pinouts don't quite match the GS450h engine control ECU.

Lexus NX - Crankshaft Position Sensor "A" Circuit (P0335) - Sfi System (lexunx.com)

hazelnut · September 10, 2023

I decided to bite the bullet and pay for some lexus-tech access. This allowed me to rule out any wiring issues. Delving into the P0345 DTC description lexus-tech provides I have a few possibilities:

* Open or short in VVT sensor for intake camshaft circuit
* VVT sensor for intake camshaft
* Camshaft timing gear for intake camshaft
* Jumped tooth of timing chain for intake camshaft
* ECM

Before I start to check the engine timing chain, I quickly popped the lid on the engine ECU, see if anything was obviously burned up. It wasn't. I also noted no EEPROMs in this ECU unlike the Hybrid ECU, so maybe this one can simply be swapped over without coding to the car?

How reliable is the timing chain ? the car 'only' has 120k miles...

HPS13 · September 10, 2023

On 8/23/2023 at 5:57 PM, hazelnut said:

(it was a bargain)

Do you still feel like it was a bargain?

hazelnut · September 10, 2023

TL,DR: Crank sensor working, still only runs for 5 seconds.

I put it all back together, connected batteries, connected tech-stream, attempted to start the car. It ran for 5 seconds, and then cut out. I saved the freeze frame data and also took a screenshot of it. I have RPM values, and no crank sensor error codes, so that seems to be magically working.

I still have this P0345 DTC. I'm not completely convinced I identified the correct sensor on the engine. I have focused on the front N/S sensor, the wiring seems correct. I've ordered another ECM to play with, and then I guess I need to pay for some more lexus-tech to learn how to check the timing chain timing.

hazelnut · September 11, 2023

14 hours ago, HPS13 said:

Do you still feel like it was a bargain?

It is certainly providing a lot of learning. I got ahead of myself as the previous dead GS450h I bought is now running great.

Last night I was thinking about this worn timing chain thing, and I don't think it can be that, as the most of amount of slack would be seen by bank 1 cams, if you follow the tension side of the chain back counter clockwise from the crank, it reaches the nearside bank 2 first , then the offside bank 1. I suspect the chain is fine, and the chain timing is spot on, but the VVT wheel is out of phase.

hazelnut · September 11, 2023

The fun continues. I spent a lovely relaxing couple of hours stripping the top of the engine down. Then I found 3 loose screws in the head, so the VVT had become loose. I assume all the intake valves are bent now. I guess it was running on 3 cylinders for my tests

hazelnut · September 11, 2023

On 9/10/2023 at 6:14 PM, HPS13 said:

Do you still feel like it was a bargain?

No compression on one cylinder in each bank. Anyone need a boat anchor?

Steven Lockey · September 12, 2023

Always a bit of a gamble.
I got mine for £1.7k from a dealer. Was fairly sure there was something wrong at that price but was advertised fault free.
Ofc the hybrid Battery was dodgy so I got £700 back off them for the repairs.

NickySB · September 12, 2023

I completed an engine tear down on mine when it developed some odd behaviour ( shaking & refusing to start on occasion) , after lots of investigation rebuilt the top end, no change, tore it down again to eventually identify a bent Conrod in cylinder 4. I would argue an engine change was easier than a rebuild but that’s just my opinion if that’s what you decide to do, unless that’s now the donor car you mention in other posts

hazelnut · September 13, 2023

14 hours ago, NickySB said:

I completed an engine tear down on mine when it developed some odd behaviour ( shaking & refusing to start on occasion) , after lots of investigation rebuilt the top end, no change, tore it down again to eventually identify a bent Conrod in cylinder 4. I would argue an engine change was easier than a rebuild but that’s just my opinion if that’s what you decide to do, unless that’s now the donor car you mention in other posts

Hi Nicky,

My current plan is to remove the engine, and install Large Li-Ion Battery along with a ZombieVerter.

Steven Lockey · September 15, 2023

On 9/13/2023 at 2:34 PM, hazelnut said:

Hi Nicky,

My current plan is to remove the engine, and install Large Li-Ion battery along with a ZombieVerter.

How is that going to work without completely reprogramming the ECU?

Car is still going to command the engine to spin up and the 2nd electric motor to connect to it to act as a generator and you can't really get around
that without reprogramming, which means you are down to 1 electric motor for power as the 2nd one tries to get power off something not their (I assume
you bypass the generator and add the power directly from the ZombieVerter when it needs power) and the CVT disconnects it from the road entirely.

So even if it works, gonna make it have what? 150hp max? Both electric motors together only generate 200hp max, I'm not sure the ratio between the two.

Sounds like a fun project, just not sure the result will be worth the work!

hazelnut · September 15, 2023

The ZombiVerter is a solution by Damien Maguire and others from Open Inverter. It replaces the Hybrid ECU in the car, comes with its own firmware and hardware to talk to the inverter. Damien has a GS450h gearbox in a BMW with MG1 locked, with power going to both MG1 and MG2. On a Dyno his project produces >225BHP out the rear wheels. Given the torque curve of the GS450h gearbox, it should actually be significantly faster 0-60 than a standard GS450h. However that is not my motivation. My motivation is to have a Battery electric vehicle that doesn't cost £30k. My reasoning is that why remove the GS450h gearbox from an already great car.

Steven Lockey · September 16, 2023

Ah, replacing the ECU explains it. Didn't know it had the ECU replacement built in. That would solve the previous issue and unlock the full 200hp.

Confused about your other statement about the BHP of the electrics? They are only rated to 200BHP together so if he's getting more than
that output, they are running above their rated maximums which would worry me slightly. Wasn't sure if you meant that on a different car
however since you mentioned a BMW. I mean they will work like that for a while but at over 10% over max, will seriously hurt reliability.

Quote

Given the torque curve of the GS450h gearbox, it should actually be significantly faster 0-60 than a standard GS450h.

I'd be interested to see how much difference it makes. I'd guess very little if any. Probably a bit faster on the 0-30 then falls away quickly
after that where the normal 450h is able to apply its extra HP to the road.

Quote

My motivation is to have a battery electric vehicle that doesn't cost £30k.

Yeah but it's not the same. Even with under the hood fully loaded with batteries, what sort of range are you expecting?
Not done the maths, but I'd be guessing 100-150 miles tops? Even that might be optimistic? Not sure how much Battery
power you can pack in there.

hazelnut · September 16, 2023

Range is not an issue for me, we have a another GS450h for long trips. But mostly it would be loocal/commute. The range will be dependant on the weight of the batteries. To avoid changing the dynamics of the car too much I plan to fit an equivalent mass of batteries to the engine. According to wikipedia the 2GR-FSE is 174kg. According to my maths the Battery capacity would then be around 36kWh. If you assume 300wh/mile => 120 miles. Used batteries for this kWh will run around £3-4k. There is the possibility of adding an extra Battery pack where the NiMh Battery was, but then things start to get expensive.

Steven Lockey · September 17, 2023

300wh/mile might be a touch optimistic given Tesla LR only gets 255 and has a significantly better drag coefficient. Personally I'd assume something like 400-500wh/mile and be pleasantly
surprised if you get more.

But if you are happy with that range, sounds like a great project.
Also give it a year or two and you might be able to swap the Battery pack over to a solid state one or semi-solid state, which would significantly increase the range and decrease charge times.

hazelnut · September 17, 2023

Hi Steven,

You could well be right. It should be easy to figure out the drivetrain power consumption by noting the kWh indication at a given speed. eg 18 kW @ 60 mph => 300 Wh/mile. Not including power to run the gazillion ECUs, which seems to take 18A of 12V power in the Lexus (4 wh/mile) , plus A/C and of course I need to add some kind of heater...