06 1.2 Emissions Fail at MOT, can anyone help?

[peg0r]

Hi folks

Couple of months ago I bought a 06 Jazz 1.2 S, with 97000miles with short MOT for driving around town.

Drove it around, did nearly 500 miles without problem. MPG good, engine very smooth.

I then took it on a longer motorway run, fast B roads and the check engine light came on. Read the code, it was

P2271 Heated HO2S 2 Bank 1 Signal stuck rich
P0420 Catalytic converter system bank 1 below threshold.

I tried clearing them, noticed the idle change slightly as the CEL went off. I drove on, it never came back.

Fast forward to this week, took it for an MOT and it failed on emissions  :'(

1st Fast idle test FAIL - CO - 0.34, HC at 245.
2nd Fast idle test FAIL - CO - 0.44, HC at 292.

After the test I scan again and notice that the P0420 code was 'pending'. I clear it again but realise the car needs work to make it right and pass.

I notice when I read the o2 sensor live data in my torque OBD app that O2S2 trim (b1) has -% output. I'm thinking I may have a duff rear (after cat) o2 sensor?

So, i've ordered 8 x NJK BKR6E-11, and both front and rear o2 sensors and plan to fit. I was also thinking of cleaning the EGR valve but the car performs really well, good starter, idle, doesnt smoke, plenty of power...

I would appreciate any and all input as I love my Jazz and need it back on the road for xmas 

[Jocko]

When I take my 06 1.2 for its MOT I always take it for a good run and really thrash it. Don't let the revs drop below  3,000 rpm and use the lower gears to keep it well up towards the red line. It is about 10 miles of open road to my MOT station and I have never had an emissions issue. Referred to as an Italian tune-up.

[peg0r]

I thought of doing so, a lot of people recommend 'cataclean' and a motorway burn before but if that o2 sensor is bad i dont know if it would ever run clean enough for it to pass emissions?

[springswood]

Sounds to me that you're trying all the right things.

The EGR clean is so easy you might as well do it. And it's an idle test so the EGR should be closed but if it's leaking I suppose it would drive HC up. Though the fact both CO and HC are high suggests the sensors to me.

Incidentally mine, with 137k miles and without any sort of Italian tune gave CO - 0.022 and HC - 21 even though fuel economy and running aren't that great.

[olduser1]

One other consideration , take a look at Forte petrol emission reducer one of my customers cars benefited from a bottle & MOT pass.