P0103 code Passat 2003 AWT engine

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P0103 code Passat 2003 AWT engine

Postby Tronic » Tue Oct 10, 2017 4:56 pm

Hi!

Have this Passat 2003 AWT engine with P0103 code. No other symptoms than - at least what the customer says - slight lack of power. The only thing I had time to check was the air mass which was 243 g/s :roll: at idle, but tomorrow morning I will continue to check voltages on the MAF connector and if needed, scope the output. I will be back then, but are there any good words to say on how to proceed with this particular car? Have never had any P0103 issues before...
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Re: P0103 code Passat 2003 AWT engine

Postby RYM6746 » Tue Oct 10, 2017 9:22 pm

Is this a digital or analogue MAF?
Last edited by RYM6746 on Tue Oct 10, 2017 9:34 pm, edited 1 time in total.
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Re: P0103 code Passat 2003 AWT engine

Postby RYM6746 » Tue Oct 10, 2017 9:32 pm

Check your fuel trims at idle (in closed loop). Then 2000 RPM.Then 3000 RPM. Then 4000 RPM. Are they good at idle? If not, do they improve when the revs get higher?. Also I am guessing this has a broadband sensor so it maybe better to see if you can get a milli amp reading on your scan tool. EOBD is the best place I have found for this pid. Go on a short road test give it WOT and see if you are running rich or lean. Before you leave just give it a quick air leak and watch which way the miliamps go, positive or negative then you can be sure if you are rich or lean during the WOT. Let me know what the results to these tests are
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Re: P0103 code Passat 2003 AWT engine

Postby Tronic » Wed Oct 11, 2017 11:48 am

Thanks for quick reply RYM6746!

It is an analog MAF on this car and for your question about fuel trims, they were only a few tenths of a percent on the plus side at idle. All that was checked yesterday, but will of course try all your suggestions and get back here if I have a time slot big enough - been quiet busy with other things being also a technician at an upper secondary school.

A couple of things that struck me when looking at at STFT (+0,2%) and the air mass which was more than 200 g/s: how does the ECU react when the air mass is totally wrong like in this example? May the engine got into limp and one thing I am not sure concerning that: could the engine still be - thinking of the STFT nearly zero - running in closed loop and manage to correct the fuel delivery?

Excuse me for not being able to do all tests you suggested yesterday, but I will be back with them.
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Re: P0103 code Passat 2003 AWT engine

Postby KimAndersen » Wed Oct 11, 2017 7:46 pm

Hello

This DTC P0103/ 16487 is set as soon as the signal rises above 5 volts for longer than 0.5 seconds (engine speed below 2000 RPM ).

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Re: P0103 code Passat 2003 AWT engine

Postby RYM6746 » Wed Oct 11, 2017 7:50 pm

In that case it should be super easy to find
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Re: P0103 code Passat 2003 AWT engine

Postby Tronic » Wed Oct 11, 2017 8:36 pm

Thanks KimAndersen and RYM6746 for reply with clarification on what pull the code!

Well then ... a few things I Think of are: internal fault in the MAF, wiring with bad insulation between 12 volt from the fuel relay and output of the MAF. That is my two Zloty even though I am Swedish :lol:
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Re: P0103 code Passat 2003 AWT engine

Postby KimAndersen » Wed Oct 11, 2017 8:45 pm

RYM6746 wrote:In that case it should be super easy to find


It depends on how stable the Maf sensor signal are under test and here I'm thinking about glitches in signal - which of course is an easy task to see with the picoscope connected.

If the signal looks good at the moment its being tested - it could lead you in a wrong direction in terms of a correct diagnostic gameplan.

Regards
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Re: P0103 code Passat 2003 AWT engine

Postby Tronic » Wed Oct 11, 2017 8:57 pm

Kim, since the readings is, and constant, over 240g/s I would bet on internal fault or wiring insulation. Headroom for the output on a working MAF would be no higher than 5 volts in theory. I will hook up my Pico tomorrow and save the file and upload it.

Regards Bjorn
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Re: P0103 code Passat 2003 AWT engine

Postby Tronic » Wed Oct 11, 2017 9:00 pm

Oh forgot to say that these figures are at idle. :shock: Should be, as I read somwhere, in the vicinity of 2-4g/s.
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