IS250 - cranks, just about to start, but doesn't

[Linas.P]

24 minutes ago, Thackeray said:

Two things I was wondering. If the engine fires, can the problem be in the immobiliser? Maybe it can, I don't know how the immobiliser is supposed to work. But I would have guessed the immobiliser would prevent the car getting as far as firing. Maybe someone who knows the answer can say one way or the other.

The second thing I wondered was about the code for the O2 sensor which controls the air/fuel ratio. Could there be a connection between whatever was wrong with the sensor and the fact that the engine fires briefly and then stops? Initially it looked as though there was a problem with the fuel but maybe the air/fuel ratio might cause a problem.

Again, it would be good to rule this possibility out. I assume the rear sensors are only to monitor the catalytic convertor but presumably the front ones contribute data to control the air/fuel ratio.

I don't know how immobiliser suppose to work either. But if you leave the key outside of the car, then it eventually cuts out the engine. It has happened to me once on old car. My girlfriend had keys in her bag and we were going with friends in 2 cars. At some point we stopped for coffee, she went to sit in another car, then we set-off and when I stopped by the next traffic light car just cut-out - and on display it said "no key - shift into P range" 😄

So immobiliser can shut the running engine. Why it would cut it in fashion it does... I have no idea.

As for air/fuel ratio my understanding that ECU takes reading from both Bank 1 and Bank 2, so even if one sensor is faulty it should at least start the engine.

4 minutes ago, ColinBarber said:

P0031 is only related to the heater circuit within the A/F O2 sensor, not the sensor itself. The ECU will drop into fail-safe but it would still run, and certainly at least splutter and attempt to fire not completely die.

Normally even if you completely disconnect an O2 sensor the engine will still run - just in limp mode.

Yes, that was my assumption as well and it was the last thing I tried - simply disconnecting the sensor. 

[bernieeccles]

I still think the immobilizer is the root cause of this and that the code from the key and the car has somehow got out of synch. Googling this comes up with various means of re synching and if I were you I would keep trying them, even if the suggested methods were for different cars. As an example.

So, what do you do if your three-year-old child DOES desynchronize your transmitter by pushing the button on it 300 times, so that the receiver no longer recognizes it? Most cars give you a way to resynchronize. Here is a typical procedure:

• Turn the ignition key on and off eight times in less than 10 seconds. This tells the security system in the car to switch over to programming mode.
• Press a button on all of the transmitters you want the car to recognize. Most cars allow at least four transmitters.
• Switch the ignition off.

[bernieeccles]

Yes I know the IS250 does not have an ignition key but there are other re synching solutions where you lock the car with the key and then unlock it then press a combination of buttons on the fob, that sort of thing. Google it.

[Linas.P]

Nothing comes-up depending on what I search, if search term is broad then discussion is always about lost keys and needing to register the keys. If I search for crank/wont start - then it goes into park/fuel pump/injector topics. If I search more specifically for B2799, then there are dozen similar threads without conclusion... people trying to reset ECUs, pull out dashes and all sort of things and there is never any solution. Or I simply find my own threads here or on reddit.

Found this document, which is for LS430, but look at the case 4... "shift lever not in P position when engine start attempted", sadly it does not have hints what to do in this case:

https://lexusy.pl/LS430/rm/rm1049e/m_05_0754.pdf

No I don't think my door was open, but as I have said I may have shifted before engine fully started.

Actually, fed up with this issue, got few local call out mechanics booked for next few days. No diagnosis no fee... But I have very low hopes for it and kind of feel like I will need to watch what they are doing, or else I won't be able to put the car back together 😄 

[Linas.P]

Yesterday I had two different mobile mechanics to come over to look at the car and they just confirmed my diagnosis. There is spark, fuel and engine seems to want to start, but after first crank ECU just cuts the spark. Leading into conclusion that it is something to do with immobiliser, basically they could not tell what to do further, so didn't even wanted to charge me for diagnostics as I basically just asked them to confit that it is what I think it is. Both suggested that my next step is to call locksmith who can program the keys to the car and for them to try to reset the key and pair it again.

Now second guy actually asked great question - he said "have you ever started the car inside this garage" and it made me realise that indeed I have never started it inside. From the time when it was delivered I parked it outside and only on the evening before the service I parked it inside for the first time. Which then LED to the theory that maybe there is interference in the garage and my issue literally being the location where car is parked. 

We took the car out and although it looked like it was about to start it still failed. However, all that said I thought that maybe I should try re-syncing ECU after taking car outside. Because if indeed that is the problem, then me re-syncing the ECU inside wouldn't have ever worked, it tries to re-sync, but there is interreference with the key, so it obviously can't finish adding the key.

Anyway that is the theory I have and I will try to push the car outside again and resync ECU in place where I have started it last time and see how it goes. Failing that my last option is locksmith and clearing and adding the keys again. 

[ColinBarber]

You should be able to read the status of the immobiliser components and engine power control when trying to start plus perform active tests using Techsteam.

[Linas.P]

I have checked some of the tests, however I am not sure all active tests are even available on my Techstream or maybe I don't know how to get to them. Either way - the ones I was able to do all checks out fine.

Contacted locksmiths and basically they don't even want to come after I explain the issue, probably for a better because it would likely be waste of their time an my time. What they said basically is that it isn't key/immobiliser issue, according to 3 different locksmiths (which probably can't be coincidence) if there would be key/immobiliser issue, then the car would not even attempt to start, won't even allow to turn on ignition. 

So they reckon it is electrical fault, something along the lines of damaged ECUs, fuses or wiring. Now I am sure fuses are good, I have tired different ECU... so what is left to check is wiring... and that is where I was stuck at the beginning of this thread... diagnosing electrical issue in such complex car like IS250 is nightmare! I need to have dash out, pull wire harnesses out and then it requires specialised testing equipment and skill set.. oscilloscopes and all sorts of fancy stuff.

[Mr Vlad]

I've seen elsewhere on other forums and even YouTube about a similar situation as yours Linas. Concensus is the actual key. And as for wiring issues, since you don't actually know the cars history and how long it's been stood there is a possibility that a rodent or two over time have chewed a wire or two. Have you priced a replacement key from Lexus? Even at a couple hundred quid it'd be worth it I think. What about finding an auto electrician and get a quote for a electrical test. Just a couple of suggestions for you.

[Linas.P]

2 hours ago, Mr Vlad said:

I've seen elsewhere on other forums and even YouTube about a similar situation as yours Linas. Concensus is the actual key. And as for wiring issues, since you don't actually know the cars history and how long it's been stood there is a possibility that a rodent or two over time have chewed a wire or two. Have you priced a replacement key from Lexus? Even at a couple hundred quid it'd be worth it I think. What about finding an auto electrician and get a quote for a electrical test. Just a couple of suggestions for you.

The locksmiths don't think so... although they haven't even bothered to come to check it out based on description of the issue, so there may still be a chance.

As far as rodent getting through the wiring, I don't think so, certainly nothing visible and I have looked it over quite a bit when cleaning the grounding points. The insulation is quite crusty, but wires seems ok. Besides, don't forget that car was running fine for nearly two weeks... if it would have been rodents chewing through the harness, then I would expect Christmas tree and no start from the beginning... based on some receipts I found in the car it seems to have been running at least until late 21/10/2021 and I bought car on 27/11/2021, so it sat for no more than a month.

Key from Lexus is £460 and that isn't in itself an issue as log as it fixes the issue, but there are no guarantees for that.

The electrician, is now my next step, because as I said it goes back into removing dash, using oscilloscopes and way to complex diagnostics for me. Some of the locksmiths have recommended some electricians for me, so will be calling to discuss this issue tomorrow. 

[Mr Vlad]

WOW £460 for a replacement key? That's gobsmacking. Hope the sparky that comes is a guddun and finds the issue and sorts it.

[Thackeray]

Is it still doing the same pattern of 1. firing, 2. not firing and screen goes blank, 3. firing, 4. not firing and screen goes blank?

If it is, perhaps there is something that can be deduced from this pattern in terms of ruling out certain types of problems. Eg can it fire if the key is at fault? Can it fire if the fuel mixture is wrong?

Another question. If it fires at step one, what happens if you wait 10-20 seconds before trying again? Does it do the normal step 2 or does it fire like in step 1?

 

[Linas.P]

On 2/11/2022 at 12:56 PM, Thackeray said:

Is it still doing the same pattern of 1. firing, 2. not firing and screen goes blank, 3. firing, 4. not firing and screen goes blank?

If it is, perhaps there is something that can be deduced from this pattern in terms of ruling out certain types of problems. Eg can it fire if the key is at fault? Can it fire if the fuel mixture is wrong?

Another question. If it fires at step one, what happens if you wait 10-20 seconds before trying again? Does it do the normal step 2 or does it fire like in step 1?

Waiting doesn't make a difference, the pattern is like:

• if ignition is in OFF position, then fires once 
• if ignition in ACC or IG position then doesn't fire at all

As well, when it is in OFF position and I try to start it, it fires once and then stalls, the car by default goes into IG position and therefore would not start. However, if I release brake, turn the car off and try it again from OFF, it would fire again every time.

Note as well, that by manually squirting the fuel into cylinders engine actually runs. So the stall is most likely because fuel get's cut. But at the same time it doesn't mean no fuel get delivered at all, aster trying multiple times cylinders get wet and there is fuel smell from exhaust. It is definitely immobiliser telling ECU "kill the engine" for some reason. What that reason is - I can't figure out. 

What locksmith told me is that if key would be wrong it won't fire at all. And as for wrong fuel mixture - it should start, but would run rough...  it could stall for sure, but not like that where it doesn't even start.  

[Linas.P]

Some update...

Car still doesn't run but according to auto-electrician they have identified what is needed. So the fault is as I suspected is to do with ID Box, the conventional solution is very very expensive one - replace half of the car computers and sync them... that is £4000+ just in parts, and then I would need to remove dash to replace everything, control module is in the boot and ECU is under the bonnet. He said they once had exactly the same issue with another customer and they got it done for £950 using used parts. In either case that is not what I want to do and to the electrician said he doesn't want to get involved either as it is massive job. 

Instead he has some ECU programmer and I have spare ECU, and he told me they were able to find the way to trick ID Box working again. Don't know the detail but that would cost me £250 if it works, so I guess it is worth the shot. One caveat - if it works, I may pay £250, but if it fails again 2 days later I will be back in square one.

Other thing, I asked why he thinks it has happened and he said this is usually to do with incorrect jump starting or Battery going flat and generally voltage fluctuations. It is kind of hard to predict, but somehow ID Box got out of sync from ECU and the procedure which suppose to resync them does not work.  I am surprised and kind of annoyed this has happened and the way it has happened. It makes sense that in auction lot it may have been jump started incorrectly, but it is still strange why it worked for couple of weeks before dying overnight. 

[Mr Vlad]

Wow. But what a good sparky you found to finally find the cause of the starting problem. Blimey 4k for new parts. Using used seems best if that was needed. Let's hope tricking the ID box works 

[MartinH]

Does your car have a sunroof? This seems a bizarre question but my IS250 suffered from a similar series of problems to those described in this thread (though I have not followed it in detail). The problem was finally traced to leakage of water from the sunroof surround into the electronics — extremely rare it appears, not least because so few IS250 have a sunroof (OK moonroof). And yes, the cost to fix the problem was nearing £4000. However this did include, possibly factitiously, new fuelling components, so I can now use E10 fuel with no qualm. It was cheaper than scrapping the car and buying a new Toyota Corolla.

[Linas.P]

It does have sunroof and it did happen after washing it... wonder if that is connected... In other hand there were no signs of leaks, but I may need to investigate further.

[Texas]

10 hours ago, MartinH said:

Does your car have a sunroof? This seems a bizarre question but my IS250 suffered from a similar series of problems to those described in this thread (though I have not followed it in detail). The problem was finally traced to leakage of water from the sunroof surround into the electronics — extremely rare it appears, not least because so few IS250 have a sunroof (OK moonroof). And yes, the cost to fix the problem was nearing £4000. However this did include, possibly factitiously, new fuelling components, so I can now use E10 fuel with no qualm. It was cheaper than scrapping the car and buying a new Toyota Corolla.

So….do you know exactly which components in the fueling system were not compatible  with E10 and subsequently changed ( to newer compatible parts I guess!) to allow you to now use E10 grade fuel.

[Alfalfa]

4 hours ago, Texas said:

So….do you know exactly which components in the fueling system were not compatible  with E10 and subsequently changed ( to newer compatible parts I guess!) to allow you to now use E10 grade fuel.

2006 and 2007 Is 250 is not E10 Ready , its the fuel pump that is the problem.

[MartinH]

4 hours ago, Alfalfa said:

2006 and 2007 Is 250 is not E10 Ready , its the fuel pump that is the problem.

As I understand it, the high-pressure fuelling components of 2006/7 cars are prone to internal corrosion when fed with fuel that has a higher moisture content. In later cars, these components were improved by the addition of an internal anti-corrosion coating. My assumption — and I admit it is an assumption — is that when the fuel system of my car was rebuilt, these later parts were used.

@Texas if it would be helpful, I can look out the the very long invoice with part numbers. PM me if you need to know this.

Referring the sunroof issue, the leakage of water into the electronics can occur when the drain from the sunroof surround gets blocked with crud. Unsurprisingly, rodding this drain through is not a scheduled service item.

Edited March 13, 2022 by MartinH
further info added

[Linas.P]

3 hours ago, MartinH said:

Referring the sunroof issue, the leakage of water into the electronics can occur when the drain from the sunroof surround gets blocked with crud. Unsurprisingly, rodding this drain through is not a scheduled service item.

In my case I only had the car for two weeks before this happened, so I don't know if sunroof drain may have been blocked i.e. I simply had no time to notice  any issues with anything was getting wet or damp... kid of the risk when buying used car... never assume that something was done to it and always assume that everything is broken. In my case I simply had no time to look around all the areas before it failed to start. 

I am kind of surprised this would involve any fuelling components, in my case those are basically all the computers controlling various body functions related with security, noting related with fuel delivery in particular. I mean nothing that touches fuel, only electronics and control units.

[Texas]

Interesting video ( I thought so anyway 😀)

whereby car had a fault occur straight after fixing something totally unconnected and this threw the fault finding process right out the window and previous garage gave up!

 

[Linas.P]

Interesting video...

As I said before the repair manual suggest that the next step (after like 27 steps of diagnostics) in my case it to check wiring for ID Box... Little problem there... somebody extremely smart in Lexus decided to put ID Box under the dash, so dash has to come out even before you can even measure any wires. In normal circumstances this is what has to be done regardless if I like it or not, but in my case the car is not worth the money to do diagnostics like that - it is £2000 car assuming the rest of the car is in good shape (which it isn't) and paying say £950 for dash out job is just not an option. 

This kind of begs a question of how these guys are planning to fix it without taking out the dash, especially if it is not just coding issue, but it is actual wire which is broken?! And the answer is - I don't know. I can guess that maybe with direct access to ECU they can "program-out" the immobiliser altogether... kind of dodgy, but to be fair I would go along with it... it is not like anyone is on lookout to steal banged-up 15 years old Lexus IS250.

It would be cool if I knew the guy like in the video which can properly diagnose the car without starting to throw parts at it and without charging £1000s for the job.

[Mr Vlad]

Wow what a ruddy good video. Total respect to proper sparkys 👍

[Linas.P]

Have not heard from the electrician for a while now, so I assume whatever they thought they could not with ECU reprograming without taking the dash out, didn't work out...

As such today I have removed the dash myself, good part is that it took just 1.5h, including bringing the Battery from home because I needed to move steering wheel away, I reckon it is doable in 30 minutes next time... and I was sort of scared of this job as I thought it will take 4 hours at least. Haven't checked much in terms of wiring, just quickly checked looms to see if somebody have touched them before and they all seems to be in good order, checked ground points and all look clean, nothing out of ordinary, some surface rust on few brackets and crossmember (but all Lexus I have seen has this, I assume condensation on bare metal), there are no signs of any leaks from sunroof, the windscreen is original... so kind of unfortunately there is nothing to report. ID Box is really tucked away begin the dash and pain to access, but all in all Power Supply ECU, ID Box, Body ECUs all look in perfect condition, no sigs of being wet, or oxidation - note as well all PCBs are covered in lacquer (basically sealed).

Next step tomorrow will be to check the wiring further and see if I can find anything interesting there. This cars is damn mystery - everything seems fine but it just doesn't run! 

[Mr Vlad]

Well done in taking the dash out in much less time than you expected. Maybe you could do a post like how to put the dash back in and others can see what's involved and not be scared of the job.

Yes a mystery regarding the starting issue but just because an electronic unit look nice and clean it may well be fried inside. See what electrical tests you can do. You seem methodical so it should be easy to do. Good luck.