kyle uk

[kylekella45]

hi am new today, i’ve recently bought a 14 plate zetec fiesta with 78k on clock, few days ago yellow engine light popped up. took it to garage an they said the code is Catalyst System Efficiency Below Threshold they said they 95% sure it needs a new one, but also said could be O2 sensors, been quoted £792 can any one help me with this is this right, don’t know much about cars thanks. kyle

 

[scotman]

I would replace both oxygen sensors and see how that affects the situation. If you have not driven the car for more than a couple of days new sensors should correct that issue. In any case, the O2's would have to be replaced. So, if you do end up needing to get a catalyst, you aren't going to spend money needlessly. You might want to have the MIL cleared when you have the O2 sensors done. Then you can quickly see if that fixed the issue.