Mil On Newly Purchased Yaris

October 31, 2009

Hi wonder if you can help . We have just helped our daughter purchase a 2002 Yaris sport.

It drove great on two test drives and for the first two days - and then the MIL light came on and wont go off. She has put all her money into the car and so we really need to make sure what we are doing in repsect of the fault. We have the fault reading which is PO420 problem with catalytic emmissions effeceincy. Every thing was re-set and then after a few miles the light came on again.

We are a little confused as we also found this on another site:

If MIL warning light remains on and Fault Codes PO420 or P0430 can be read off ECU via OBDII port then car needs an ECU software upgrade

How do we know if it is the software upgrade ? or sensors? of catalytic convertor?

We purchased the car privately by the way - and it is running absolutely fine with no other problems

Thanks

November 1, 2009

Hi Janice, it sounds like it could be the lambda sensor or the 02 sensor at fault.

Maybe the MAF sensor needs cleaning aswell. ;)

November 1, 2009

Hi Janice, it sounds like it could be the lambda sensor or the 02 sensor at fault.
Maybe the MAF sensor needs cleaning aswell. ;)

There is a very good fuel-additive type of system cleaner by the name of "FORTE", which is well known in the trade, and is available in petrol, or diesel variants. I used the diesel version for 8 years, 3 in a Rover 25 TD, and 5 in a Yaris D4-D. It costs £7.50p + VaT, from my Ford dealer, but is dearer elsewhere.

The point is, it cleans out the fuel system from the tank, fuel injectors, upper cylinders, lambda probe etc., and results in clean emissions, and accurate fuelling, and can clean the Cat. It does more than the old REDEX. Mercedes have been using it, only recently changing to an alternative source of a similar product.

The 400 ml bottle treats 100 litres of fuel, and has a rapid effect.

I am now using the petrol version, in my '58 reg Fiesta Zetec Climate 1.25. I have had the emissions checked, and the levels are way below the specifications, and my only mods are Denso Iridium Tough sparkplugs and a Pipercross panel air filter. There is no octane improvement, or lead replacement content, so it can't harm your engine. (my engine can't sense high octane, but my wife's Aygo Platinum can use 95 or 98 RON).

November 1, 2009

Hi Janice, it sounds like it could be the lambda sensor or the 02 sensor at fault.
Maybe the MAF sensor needs cleaning aswell. ;)

There is a very good fuel-additive type of system cleaner by the name of "FORTE", which is well known in the trade, and is available in petrol, or diesel variants. I used the diesel version for 8 years, 3 in a Rover 25 TD, and 5 in a Yaris D4-D. It costs £7.50p + VaT, from my Ford dealer, but is dearer elsewhere.

The point is, it cleans out the fuel system from the tank, fuel injectors, upper cylinders, lambda probe etc., and results in clean emissions, and accurate fuelling, and can clean the Cat. I does more than the old REDEX. Mercedes have been using it, only recently changing to an alternative source of a similar product.

The 400 ml bottle treats 100 litres of fuel, and has a rapid effect.

I am now using the petrol version, in my '58 reg Fiesta Zetec Climate 1.25. I have had the emissions checked, and the levels are way below the specifications, and my only mods are Denso Iridium Tough sparkplugs and a Pipercross panel air filter. There is no octane improvement, or lead replacement content, so it can't harm your engine. (my engine can't sense high octane, but my wife's Aygo Platinum can use 95 or 98 RON).