EML issues

[Fourbears]

Hi there, I am hoping that someone might be able to help me. The EML keeps coming on on my 2000 Yaris 1.3vvti SR despite replacing the MAF sensor and the front cat sensor. I am at a loss now as to what it may be so if anyone has any ideas I would gratefully accept them. I did try a fault code reader and it came up with bank 1 lean which indicates one or other of the sensors I have replaced, or so I am told. I have disconnected the battery each time for more than 15 mins to reset the ECU but after a few miles the light comes on again. Any ideas?
Thanks in advance.

[Bluevitz-rs]

Have you checked for vacuum leaks?

[Fourbears]

Hi yes I did, as far as is possible. I forgot to mention that.

[Bluevitz-rs]

how did you check all areas?

[Fourbears]

By re-seating all the pipes and checking for splits etc. Of course there may be pin pricks that can easily be missed. It seems that a vacuum leak is the culprit.

[Bluevitz-rs]

It's a lot easier to use a spray like starter fluid or carb cleaner on every joint including where the manifold bolts to the head.

You should also check your plugs for any one lean cylinder.

[Fourbears]

Thanks for the suggestions but I have found the culprit - the cat has failed. I managed to get the codes read properly and the cat came up straight away. Looks like the end of the road for this one!

[Bluevitz-rs]

What code numbers came up.

A bad cat is P0420

[Fourbears]

Thats the one! As the headlamps are somewhat opaque, the brakes need either new drums, discs or both plus the cat and it has 162k on it it is not economic, for me, to repair it for the MOT due in Feb. So it will have to go closer to the time.