Whilst my HiAce experience (petrol & diesel) is extensive (cough-they tend to live forever with minimal love), I am new to the V6 in the Vellfire. I’m currently with my (high mileage) Vellfire in Thailand and I have 2 questions:

1.      I’m getting engine and (VSC) flashing lights on the dash and using the FIXD tool it’s determined that I have a faulty Oxygen Sensor heating circuit on Bank1 Sensor 2 and also getting System too Rich codes on both banks.

It isn’t an ‘urgent’ issue, but I have had ithe issue for a few months (6500kms) and I have taken it to official Toyota garages in Pattaya, Rayong, Aranya Phratet, Sa Kaew, Muak Lek, Chonburi, (7) all of whom (as far as I can tell-my understanding of Thai is sh*t) have said – too difficult, can’t get the parts, don’t have the diagnostic tools. Toyota 1988 Korat have been excellent in fixing my aircon but again have ‘avoided’ the dash lights and codes ref the oxygen/fuel sensor issue.

They have said it’s 45 days to get the parts from Toyota in Japan, and they can’t tell me which part. I’ve offered to buy all four sensors and the MAF (about US$900 up front) but still no joy…

The van drives amazing, has no issues with pick up, or power or fuel consumption and I could probably ignore it, but the flashing VSC light (albeit orange) keeps making me think I’ve left my indicators on, so end up confusing the other road users whether I’m going left or right or straight on!

Amayama japan will supply to uk in about 10 days so should do thailand in a lot less with toyota parts

Thanks for your response Terry, it's not getting the parts that are my worry (Megazip have been excellent), it's finding a garage/mechanic that is prepared to diagnose the problem. I could spend a grand on the sensors and it's something else. It's a cultural thing I think, people would rather say no than take the responsibility - not sure. I'm just lucky to be driving a V6 Vellfire around Thailand! :-)

Sorry cant be any help, seems to be plenty dealers https://www.toyotalibra.co.th/Home:!Home

Have you got a JOBD reader? that would give you the error codes that would help track down the issue. Once you know what the problem part is you can get the part and any special tools you need, or at least a garage will have a better idea of the work required.

Thanks Gamith, I've already got the codes P0037 HO2S Heater Control Circuit Low Bank 1 Sensor2 but before that I have had P0172 System too rich bank 1 and P0175 System too rich Bank 2.

The sensor is there to do a job of sensing and if it senses something is wrong it tells the ECU. I've ordered all of the MAF, Oxygen and Air Fuel sensors as we have to rule out faulty sensors before we can rule out if there is a fault that is causing the sensors to do their job.... fun and games on a 16 year old 300,000km V6 Vellfire that still drives like powerful luxury !

Must be the sensors as it doesn't affect the driving!

Does your exhaust smell rather too 'petrol-y'? mine was so I tested for codes and I was getting P0171 "system too lean (bank 1)"

Cleaning the MAF didn't help - the error would come back after clearing it.

What fixed it for me was changing the fuel Lambda sensor which, on mine, was a struggle as the previous mechanic had forced the sensor into place and had damaged the thread.

An M18 x 1.5 tap and die cleaned up both the thread on the exhaust and the new sensor which I purchased - I would warn to be on the lookout for ones with the correct plug on the end as the cheap ones come with bare wires that need to be housed in the original socket (as the supplied ones don't stand a chance of fitting) and are bound to cause issues.

I ended up getting this one:

https://www.autojapspares.co.uk/toyota-alphard-anh10-anh15-24-front-fuel-ratio-sensor-34437-p.asp

Which is rather expensive compared to the cheaper ones, but arrived quickly and was a straight plug in.

 

If you haven't located the fuel lambda sensor look at the exhaust manifold cover behind the radiator, that would be the bank 1 sensor. As one of yours is saying bank 2 that will be underneath - see the second picture, on the exhaust under the car - trickier to get to.

 

I also changed the fuel filter and the air filter - which may have helped but less so that the sensor I would say.

I hope this helps - though I don't know about the heater control circuit I'm afraid.

Thanks Paul, mines the 3.5L V6 so I have 2 'banks' of 3 cylinders but trying to find the 'pre and post cat sensors has been confusing. I've ended up ordering them all, even though the codes pointed at one, I'd rather not be off the road for 2 months waiting for parts! Cheers I'll share when it's fixed (fingers crossed)

There are a few videos on YouTube that explain where each sensor is located.

Search for 2gr-fe sensors

19 hours ago, Trevor G said:

Thanks Paul, mines the 3.5L V6 so I have 2 'banks' of 3 cylinders but trying to find the 'pre and post cat sensors has been confusing. I've ended up ordering them all, even though the codes pointed at one, I'd rather not be off the road for 2 months waiting for parts! Cheers I'll share when it's fixed (fingers crossed)

Ah - good point, that would mean a different bank 2 then :-) Good luck in getting the replacements fitted.