P0171

[mountains013]

I am a newbie here. I have a Golf Gti BWA Eng. code I have had P0171 reccuring The diagnostic VCDS said inlet leak the tech suggested manifold this was given the all clear by my technician but a split pipe on brake booster valve was found, fitted a complete unit found another vac leak fixed this. The idle speed was fluctuating found faulty PCV new one fitted, new oil cap and new dip stick o ring. The car runs really well idle perfect but my Foxwell NT204 scanner is showing an orange warning light. No codes shown or stored or pending, Mil off. I am a bit mystified by this, any help appreciated. I am a 67yr old mechanic trying to get my head round scanners and diagnostics for my own use

[landroverman1958]

Why dont you use mode 6 to see if there are any pending codes?also look at your fuel trims in obd2 to verify a lean/rich condition.

[mountains013]

Thanks for your reply. No codes stored or pending Mil never been on. My last f/trims after a 27 mile drive Short -4 long 8.6 The car had a very erratic idle which I have now sorted vac leak

[liviu2004]

I would say, fixed, move on, no worries.

[mountains013]

I had usual problem today found a split hose fitted a new one idle back to normal went for a 10 mile run fuel trims on returning shrt1.6 long 5.5 what constitutes a full cycle run?

[Iver]

what constitutes a full cycle run?

A Minimum Quarter tank of Fuel is one of many Prerequisites that have been overlooked by some. So much easier to achieve the drive cycles on the manufacturers test tracks as opposed to the busy roads we have where it is not easy, Especially between 9 - 5am ?

[mountains013]

Thanks. I'm lucky I live on the edge of the Brecon Beacons so lightly trafficked roads plus have one road where I can have a blast

[mountains013]

Did 50mls this morning 3000 to 4000rpm refuelled code cleared idle settled green light in scanner, no codes not saying fixed but fingers crossed