# P0103 code: mass air flow sensor (high input)



## dudeman08 (Feb 23, 2009)

alright, im at a loss for words. ive spent 2 weeks diagnosing this issue and searched everywhere for answers. my maf sensor is not getting power. ive tested for voltage at the connector and checked for circuit continuity as-per what my bentley manual said. terminal 3 on the connector is getting no voltage and its also an open circuit. i checked the connector and probed through the insulation of the wire about an inch or two behind the connector and nothing. my maf is a brand new bosch, and i even tried 2 other known good used bosch sensors as well, but no dice. im running really rich, low power and sluggish at part throttle and misfiring above 3k rpms. if i go wot, its perfectly fine and pulls hard as hell. any and all help would be nice. car starts up and runs fine, but you can smell just how rich its running (its obnoxious). going like 10 miles and using a 1/8 of a tank is getting old really fast, esspecially since im using 93 octane (mods require i use it). car is a 98 jetta 2.0 non-california emissions. thank you in advance.


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## dudeman08 (Feb 23, 2009)

bump.


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## Anony00GT (Mar 6, 2002)

Please post a complete mod list. Didn't you already have another thread on this problem, or was that someone else?

Battery voltage is supplied to the MAF via the fuel pump relay. You should be testing for power with the engine running, not just with the key on.

Can your scan tool display a datastream?


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## dudeman08 (Feb 23, 2009)

damn im retarded. ive been so tired lately from workin on everyone elses cars for the past 3 weeks and spending the little spare time i have with mine. i overlooked that i need the engine running to have a reading from the maf. :facepalm::banghead: ive got a serious list of mods, ill post it shortly. yes, my scan tool does in fact have a live data stream. when the car misfires, the pre-cat o2 sensor drops from 0.450~ volts to 0.350~ volts and then spikes back up to normal and the car smooths out. it sometimes does it rapidly, just a few bucks, but in very quick succession. i forget what the maf readings were. ill double check tomorrow. this issue is only at part throttle above 3k rpms, and is sluggish and down on power unless you go wide open throttle, then i wakes up and runs great and pulls super hard and doesnt buck or anything.


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## Anony00GT (Mar 6, 2002)

Ha we all make mistakes 

Seriously though, need a mod list before we proceed with diagnostics.


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## dudeman08 (Feb 23, 2009)

haha. well, the mods list that is acctually done to the engine is the following:

built head (p&p, milled, dual valve springs, titanium retainers, light weight lifters)
276* cam
USRT long runner intake manifold
Injen cone filter on a brand new Bosch maf
deramped throttle body (new, VDO)
TT 4-1 race header
Neuspeed cat-back
MSD blaster ss coil
a/c delete
light weight crank, tensioner, alternator pullies (gruvenparts)
TT light weight intermediate shaft gear
TT adjustable cam gear
ACT stage 1 clutch 
Eurospec light weight flywheel
low temp t-stat and fan switch (180*)
NGK iridium plugs with NGP wires
Autotech q-chip (have a custom race file from TT, but dont want to put it in unless im at the track)

im sure i might be missing something, but thats the jist of it.


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## dudeman08 (Feb 23, 2009)

bump.


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## Anony00GT (Mar 6, 2002)

Using a scan tool, record the MAF reading (g/s) at idle at operating temp, then the highest reading achieved during a WOT blast to the redline in 2nd gear.

Replace the de-ramped TB with a proper stock one, perform ADP. OBDII cars HATE ported/deramped throttle bodies.


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