Error code P0420 and P0128

[rjs]

Hi

I've had the car (v70 2.4 auto, x Reg, 2000) for a couple of weeks and the emissions light is now on. To start with it kept going off again but now it seems to be a permanent fixture.

So I plug my cheap scanner to the car and got the follow error codes
P0420 - Catalyst performance low
P0128 - thermostat not up to temp

Any advance? I've read that the 2 can be connected, low engine temp can lead to poor performance by the cat. I have noticed that it seems to run a little on the cool side.

On the other side of things I know the cat hasn't been changed and the cars done 126,000 miles so maybe it does need changing. Also when I read the codes I hadn't warm the engine up, could that of given a false reading and I should concentrate on the O2 sensors and cat?

Any advice would be great.

Also in the list of codes read by my scanner I got the same codes with a * next to them. Any one know what this means? I'm new to fixing moden(ish) cars. I normally work on things from 1972 and earlier and they don't have codes, they just break!

Thanks
Rob

[rjs]

I've just driven it home and the P0420 code has gone now and taken the emission service light with it. the P0128 code is still on there and there is a P0075 code too. (It was there yesterday, but I forgot about it)

[billynomates]

Ive no idea of the codes, Im sure someone will be along to help soon.

But if the car is running cool and the temp gauge is not sitting somewhere in the middle of the scale, I would suggest that the thermistat maybe on the way out.

[rjs]

I'll check that, thanks. I've just done another trip out and the temp is right in the middle. And the emission service light is back on!