VW Polo emissions fail

DAVIDI · 02-09-2018 11:25PM #1

Just bought a 1.2 VW Polo 2006. It had failed the nct on high emissions on the high idle.
Lambda was 1.10 (Should be between 0.97 and 1.03) co was 2.08% (should be less than 0.20%) HC was ok.
There was a check engine light on and the codes 16804:catalyst system bank 1 efficiency below threshold and 16556: Fuel trim bank 1, system too rich.
Any ideas on what to replace?
There doesnt appear to be any exhaust leaks

Alanstrainor · 03-09-2018 12:14AM

Googling those codes suggests exhaust leaks to be a likely cause of your issues. But there's also suggestions of failed o2 sensors. I think I'd want the exhaust checked properly.

BorneTobyWilde · 03-09-2018 01:13AM

Usually the converter on these polos, costly enough to buy and then fit. Would cost around 300 and to fit maybe 100 if no other issues.

marzic · 03-09-2018 03:33PM

About 15 yrs ago I had a '95 carina e, tested it 3 months early and it failed emission test. I dosed it every couple weeks with fuel additive (and skipped retest) till the nct due date and it passed. Would you give that a go?

DAVIDI · 08-09-2018 11:44PM

Thanks for the advice lads.
I gave it a good service, dipetane, cat cleaner, cleaned the map sensor and throttle body.
Replaced the 2 oxygen sensor with 2 off a polo that recently passed the test.
Had a retest this evening and still failed slightly on co.
Is it time to change the cat?

VW Polo emissions fail

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