17559 long term fuel trim

[bvs]

This error code crops up occasionally LOL
I just keep clearing it,I did change the CTS (genuine VW part) a couple of years ago,which cut down on the reocurrences.
I just wondered what else might be the cause.
Car starts and runs well,no obvious issues.
Just curious as it is too cold up here for serious work at the moment.

[bvs]

I posted the same question on Briskoda and Wino kindly posted this list...

For these engines 17559 is defined as :

Bank 1, mixture adaptation

range 11)

Below leanness limit


The suggested lines of enquiry for that code are:

– Test injection valves ⇒ Chapter 24-3

– Test fuel pump ⇒ 1.4/55; 1.4/74 Engine - Mechanics;

Rep. Gr. 20

– Testing intake system for tightness ⇒ Chapter 24-3

– Inspect exhaust system for leaks ⇒ 1.4/55; 1.4/74

Engine - Mechanics; Rep. Gr. 26

– Check exhaust gas recycling system ⇒ 1.4/55; 1.4/

74 Engine - Mechanics; Rep. Gr. 26

– Inspect activated charcoal container system for

leaks ⇒ 1.4/55; 1.4/74 Engine - Mechanics;

Rep. Gr. 20

– Testing lambda probe and lambda control upstream

of catalytic converter ⇒ Chapter 24-4

– Testing lambda probe and lambda control downstream

of catalytic converter ⇒ Chapter 24-4



First thing I'd check is the brake servo vac hose, but I seem to remember you've been there?

[bvs]

The last couple of times that the EML has lit has been right at the end of a journey (at least 30 miles) and whilst parking the polo,I am not sure if the cold ambient temps are making the problem worse .
The car (thus far) has been starting/running ok so happy to live with it through the next month unless it deteriorates.