P0172 Engine Code
Discussion
Hi All,
I have a 1999 Yaris which has recently had the check engine light come on with code P0172 - System Too Rich.
I've tried using super unleaded fuel, also tried cleaning the MAF sensor which helped make the acceleration smoother but the check engine light came back 3 days later.
Every time I reset the light, it comes back within 3 days and it only comes back on when the car is idling.
The MOT emissions report shows that the CO is just under the pass limit.
So i'm thinking it's either an oxygen sensor or the cat. Any thoughts?
Thanks,
Ross
I have a 1999 Yaris which has recently had the check engine light come on with code P0172 - System Too Rich.
I've tried using super unleaded fuel, also tried cleaning the MAF sensor which helped make the acceleration smoother but the check engine light came back 3 days later.
Every time I reset the light, it comes back within 3 days and it only comes back on when the car is idling.
The MOT emissions report shows that the CO is just under the pass limit.
So i'm thinking it's either an oxygen sensor or the cat. Any thoughts?
Thanks,
Ross
GreenV8S said:
Is it a hotwire sensor? Their sensing elements are fantastically sensitive to contamination and I imagine would be very tricky to DIY clean.
I think it is, but considering i've got an increase in performance since cleaning it and the light still comes on, i'm thinking the problem lies elsewhere. 
Edited by rossh123 on Tuesday 26th September 20:27
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