1.4 16v engine 17559 long term fuel trim

[YS53]

This error code crops up occasionally,I can reset with scan tool but eventually comes back a couple of weeks later.

It is an AUB engine and actually on an 02 Polo but reads across to Fabia etc

I changed the CTS a couple of years ago (genuine VW part) and this cut down on the reoccurencies but did not stop them completely.

The car starts and runs fine - no obvious signs of any issues.

Just wondered if any ideas ?

Edited 29 January, 2019 by YS53

[Breezy_Pete]

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?

[YS53]

Hi Wino - no I have never mentioned the servo hose - you must be getting me mixed up with some other good looking forum member 

Thanks for the checklist,I will not be looking at the car until the weather (hopefully) warms up - it is a little parky up her at the mo.

 

rgds YS

Edited 29 January, 2019 by YS53

[Breezy_Pete]

9 minutes ago, YS53 said:

getting me mixed up with some other good looking forum member 

 

My apologies.

 

[YS53]

Hey no probs 

Interesting checklist - there may be a slight  exhaust 'blow' - how sensitive would the fuel system/exhaust sensors be to that ?

[Breezy_Pete]

I guess anything upstream of the rear lambda sensor could cause issues, anything further back than that would struggle to matter, I think.

 

[fabdavrav]

Having owned this engine....the two lambda sensors are quite sensitive....so "IF" there is a leak as you suggest & its in the exhaust system & between the two lambda sensors it would be enough to trip a fault code..

 

basically/simply put you have exhaust manifold...then one lambda sensor then two cats then, another lambda sensor..the last being under the gearstick area in exhaust tunnel....& between the cats you have the flexi section & joins.

[YS53]

Thanks Fabdav - I suspect the exhaust leak is further back but I am trying to ignore the minor problems until (hopefully) the weather warms up.

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 ( minus 8c overnight LOL - I know it is colder where you live probably !).

The car (thus far) has been starting/running ok so happy to live with it through the next month unless it deteriorates.

 

rgds YS

[YS53]

On 29/01/2019 at 14:16, Wino said:

For these engines 17559 is defined as :

 

 

– Testing intake system for tightness ⇒ Chapter 24-3

 

 

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

A couple of niceish days up here means I have started to do MOT prep work and a little light maintenance on our 02 Polo 1.4 16v.

 

I had a good look round the engine bay at vacuum hoses and visually they all look ok and in good condition.

 

The Breather Hose from the Oil Separator to the Air Box has perished and has quite a few splits in it,I am pi55ed off about that because I replaced it when I changed the Oil Separator in dec 17 (only done 10,000 miles) - I have ordered one from ebay but thus far have failed to find a new Hose made by a reputable manufacturer - the last one was made by VAICO (V10-2937) but obviously made out of really cheap/crap material LOL.

Any recommendations for a reasonable quality breather hose would be much appreciated.

Edited 25 February, 2019 by YS53

[Breezy_Pete]

47 minutes ago, YS53 said:

The Breather Hose from the Oil Separator to the Air Box has perished and has quite a few splits in it

 

 I have no experience of this hose, sorry. The B-series engines have the breather output going to the inlet manifold instead of the airbox.