samanaslt

On 4/28/2024 at 6:00 PM, Linas.P said:

It is quite simple really, the sole purpose of oxygen sensor is to check if there is oxygen in exhaust gas. Hole lets in oxygen from outside and therefore makes oxygen sensor to incorrectly read like there is unburn oxygen in the exhaust, so the ECU thinks that it needs to inject more fuel to match the excess oxygen, as such too much fuel gets injected, whereas there are actually no excess oxygen and you end-up with unburnt fuel and thus petrol smell.

This most of the time results to incorrect error code P0420/P0430 displayed, because ECU then assumes it is Catalytic Converter fault for not burning excess oxygen and fuel, system simply does not account for the possibility that there could be hole in the exhaust providing this extra oxygen. As suggested, the most common reason for this code is exhaust leak near oxygen sensor.

Cats rarely (if ever) fails on these cars and when they do fail that happens at 200k+, but usually the entire exhaust rusts and crumbles arounds the cats before the cats themselves fail. So the common reason for cat replacement is usually rust, not that cat is no longer works. 

Went to couple of different places and indeed there is multiple holes in exhaust system, but the main culprit is driver's side midpipe to cat flange. Huge hole developing there. 
I was told in 2 different places that they are not doing flanges and they would need to change midpipe with cat 'pipe' which by the look on internet is quite expensive. 

Is it worth to try custom exhaust places to see if I can get new midpipe and weld new flange to cat pipe? 

Also, petrol smell is not coming from exhaust system after all, found a small leak on driver's side just before rear wheel, kinda underneath rear passenger driver seat. 
Not sure if it worth to make another topic, but mechanic said that they cannot really see where exactly it comes from and it would need several hours work to find out. 
From observation could be seen that it coming somewhere from top of tanks. 

As now I got less than half tank of petrol left, I noticed that petrol smell disappearing and its not as strong. 
I suspect this to be a hole in the tank at higher place as when  i had full tank, it was quite intense smell. With one small drop of petrol developing on road after keeping car overnight.  


Could somebody please tell me if it is actually worth to try to fix these issues, as I believe exhaust + plus petrol tank change would be very expensive? 

Thank you. 

41 minutes ago, ColinBarber said:

Exhaust leak then upstream sensor then injectors should be inspected first in that order before considering the cat itself is at fault. 
 

Unlikely to be something common such as the MAF sensor if only one bank affected. 

I had some holes fixed back in October, as I had this warning coming after driving hundreds or thousands of miles. Never had petrol smell though.

After fixing havent had this warning till now.

I had to overpass cars on higher revs, so perhaps pressure did made a hole somewhere again.

How could a pinhole on exhaust cause petrol smell?

Thanks

From last weekend's small trip of 300 miles engine light showed, upon checking code found out that it is P0420 - Catalytic converter system, bank 1 - efficiency below threshold. 
On different noncontinuous monitor screen it shows that "Catalyst Monitor Bank 1 - MID$21, Value 0.03294 - Minimum is 0.038735, Result - Failed 

Once error removed, light will come back after around 15 miles. 

Also there is Petrol smell outside the car, smell strongest next to exhaust tips. Currently there are no other symptoms and car runs smoothly. 

Could anyone advise, if this is indeed upstream oxygen sensor failed which needs replacing? Car currently just under 150k miles. 

Thank you. 

31 minutes ago, ColinBarber said:

Two things normally cause this, either a small leak in the exhaust or a faulty O2 sensor - not the sensor reporting the fault but the upstream sensor.

It could be something else like the MAF sensor, or actual a Cat but normally its exhaust or one of the two upstream O2 sensors.

Ok, will try to go for fixing exhaust. After all it was picked up on MOT, however on normal visual inspection we could not see any soot. On app it reads as

OBDII: Catalytic converter system, bank 1 - efficiency below threshold. 

Which side is that?

Also any suggestions for that rough idle? 

Hello, for a while I have started to get p0420 code. After removing it with OBD reader it will appear again at random intervals, mainly when doing longer journeys. Intervals can be random 800 miles to 60 miles and so on, just random. Might appears more often when engine working harder like on North wales roads. Any ideas what that could be? On MOT done last year November it says there is small exhaust leak, could that be the case? 

Also, not sure if problem is related, but sometimes I am getting rough idle where rp falls bellow 700 rpm, and car doesnt feel very smooth, on rare occasions it goes to 500 rpm or even 400 rpm (only had that at cold winter morning before changing spark plugs) and car start to shake. It doesnt happen all the times, noticed it occurs more often on humid days, and colder humid mornings. I have cleaned valve throttle body and changed spark plugs. While ECU is learning there was no rough idles, but soon after learning it start to rough idle again. Any ideas? BTW, car got around 120k miles. 

Thank you. 

37 minutes ago, Texas said:

If any fuse supplying this circuit has indeed blown then it is likely that something else will now not be working also, as there are very few (low powered) circuits that have their own dedicated fuse. 

Have you read your owners manual if your car if different from manual posted above.

 

It's all sorted now. As I mentioned this Lexus doesn't have optional 'Park Assist' (as shown in manual) installed, however it does have LPA400 (Lexus parking assist) installed, possibly by previous owner. After finding manual on internet, manual mentions that 'optional button' to disable system can be installed in the trunk. After taking a look I found a button in the left side of a  trunk, probably got pressed accidently when I was on a trip with fully loaded trunk. I must say it's a terrible place for a button.  Anyway everything is working now. 

4 hours ago, Texas said:

Is your park assist actually turned ON? Should have a green icon in right side of dash if it is.

 

I believe my car  doesn't have park assist (I only have reverse proximity sensors with beeper, no visuals whatsoever), I never had that light and it was working, same on 220d I had, there was reverse proximity sensors but no P light. 

Hello, got Lexus Is 250 SE auto. Got a problem that sound from reversing beeper dissapeared. It was working all fine, and then suddenly after a trip it doesn't work. I've only got reversing proximity sensors and it was emitting beeping noise closer I was getting to obstacle, also there was a beep sound when I put car in reverse, it doesn't do that sound either.  

I don't have navigation screen, radio works, and I never had green P light, and I don't see option to turn parking sensor on satellite switch. Any ideas what happened? Is there specific fuse to check? Thank you. 

12 hours ago, steve2006 said:

Given the HG is a known problem with this engine the chances are it will be the gasket. Lexus extended the warranty some years ago due to the many problems with the diesel engines used, many vehicles ended up with virtually a new engine!

Could some sort of HG sealant help out on  220d with situation I have? Perhaps it's  a small leak? 

On 4/23/2019 at 7:58 PM, steve2006 said:

Ask your local MOT tester to sniff the air in the coolant reservoir with the emissions probe, if it detects exhaust gases this would confirm head gasket issues. You could also have a cylinder pressure test performed where high pressure air in then look for bubbles in the reservoir.

Done chem test on coolant reservoir, yes fluid changed colour to green. Exhaust gasses getting in somewhere into cooling system. Can it be EGR cooler or anything else. Or only answer is HG? How to know for sure? 

On 4/18/2019 at 9:22 PM, ColinBarber said:

Almost certainly the head gasket I'm afraid. Get the engine pressure tested (again) to confirm.

A stuck thermostat could cause this issue, or trapped air in the cooling system which expands when hot and pushes out the coolant, but these are both very unlikely given known issues with this engine and loss of coolant through the expansion overflow being one of the clear signals.

Yeah, but if that would be a head gasket, would it not being showing any other symptoms in those 6 months I've been driving? 

Also sometimes I can hear some bubbling sound behind dash when starting car, but after opening coolant bottle cap sound disappears for a week, and then it reappears. 

Hello, I have an issue with my IS 220D, 08 plates,  117k miles. 

I bought car November 2018, only problem I noticed is that coolant is leaking through overflow pipe on coolant reservoir tank.

Higher revs on engine, higher coolant goes in coolant tank till it overflows. And just usually spills out till it just below low line. 

After reading these forums back in December, I went to do head gasket test.

Test came clear and they just recommended me to change cap. 

Bought brand new genuine cap from dealer, problem still exists. 

I've been driving car everyday since November around 5k miles, coolant temp always just bellow middle, never attempted to overheat, no smoke, no mayo on cap, no warnings on dash.

It never been issue except that it splashed coolant all over engine bay. 

Can somebody please explain to me what's happening, because local garages have no clue.

Thank you.