My P0102 (MAF Circuit Low Input) SOLUTION
09-03-2012, 01:46 PM
#1
My P0102 (MAF Circuit Low Input) SOLUTION Gents,
Maybe this is a known solution, but I did not find it in my searches.
Just got my car up and running after 7 months of R&R of most every component outside the passenger compartment. I am running on a Frost tune for break-in/shakedown purposes and threw an SES light almost immediately on start-up.
Relevant to this thread I have an FTP 104, TSP 5-wire 100mm MAF w/ Racetronix adapter harness, NW102 and Mamofied FAST 102. My only motor related code was P0102. I noticed on the autozone code scanner that the MAF was not just low, it was not responding when I would blip th throttle. . .I had the MAF in backward so I fixed that. Still I see nothing and no response to throttle input. At the MAF end (5-pins) of the Racetronix harness I see the +12V and +5V expected relative to ground (pin B, black wire). . .so I knew it was either the MAF or the pinout to the MAF. I also noticed that I had 12V on the yellow wire and 5V on red. . .that seemed odd to me as an electrical engineer.
I went to Racetronix site and found the pinout below which corresponded to my harness' wiring shown in the picture below. . .notice that the red and yellow wires are switched relative to the car wiring. If you switch the red and yellow wires as I have edited in the racetronix table (match the wires to the OE harness) it should work if you have no other issues. I'll tell you how to do that below.
To rewire per the edited diagram above simply remove the wire strain relief at the back of the Racetronix 3-pin connector that the OE MAF harness plugs into. The strain relief comes off easily with no tools. Then use a small flat bladed screw driver to push each contact in the direction of the arrow while pushing the wire/pin back out of the connector. I removed all three wires and then put them back in in the correct order then reinstalled the strain relief. That's it, you're done, it'll work now, no more P0102.
. . .I am going to shoot racetronix a message to let them know they appear to be building the cables incorrectly.
Maybe this is a known solution, but I did not find it in my searches.
Just got my car up and running after 7 months of R&R of most every component outside the passenger compartment. I am running on a Frost tune for break-in/shakedown purposes and threw an SES light almost immediately on start-up.
Relevant to this thread I have an FTP 104, TSP 5-wire 100mm MAF w/ Racetronix adapter harness, NW102 and Mamofied FAST 102. My only motor related code was P0102. I noticed on the autozone code scanner that the MAF was not just low, it was not responding when I would blip th throttle. . .I had the MAF in backward so I fixed that. Still I see nothing and no response to throttle input. At the MAF end (5-pins) of the Racetronix harness I see the +12V and +5V expected relative to ground (pin B, black wire). . .so I knew it was either the MAF or the pinout to the MAF. I also noticed that I had 12V on the yellow wire and 5V on red. . .that seemed odd to me as an electrical engineer.
I went to Racetronix site and found the pinout below which corresponded to my harness' wiring shown in the picture below. . .notice that the red and yellow wires are switched relative to the car wiring. If you switch the red and yellow wires as I have edited in the racetronix table (match the wires to the OE harness) it should work if you have no other issues. I'll tell you how to do that below.
To rewire per the edited diagram above simply remove the wire strain relief at the back of the Racetronix 3-pin connector that the OE MAF harness plugs into. The strain relief comes off easily with no tools. Then use a small flat bladed screw driver to push each contact in the direction of the arrow while pushing the wire/pin back out of the connector. I removed all three wires and then put them back in in the correct order then reinstalled the strain relief. That's it, you're done, it'll work now, no more P0102.
. . .I am going to shoot racetronix a message to let them know they appear to be building the cables incorrectly.
09-03-2012, 09:45 PM
#2
I wanted to say explicitly here that this thread is in no way meant to bash racetronix. Even this harness is very well made with the right connectors and top shelf technique and I'd buy it again. I was stoked to find the issue and I hope it helps someone out.
. . .and that is my blood on the PS cooler. . .an offering to the LS1 gods.
. . .and that is my blood on the PS cooler. . .an offering to the LS1 gods.
09-29-2012, 11:34 PM
#4
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rabidweasel, i to had a wiring issue at my maf 5 pin mine was casper adapter. i have an 85mm delpi and used my stock pin out for 02 z28 3wire maf 2 wire iat,cross over to an 02 gto maf pin out everything a-ok ecept the iat wired backwards . it's a thermistor and i don't know if flipping the wires would cause malfunction. then i looked at the pcm pinout of the red block and noticed that each wire had a specific pinout number so i guess the pinouts have to be in the correct position ??? rewired to correct and a new maf because the other maf (brand new) was reading -38 degrees with the outside temp being 77 degees . i don't know if iat wire reversal had anything to do with it?? suggestions?? answers?? the oldman....
09-30-2012, 06:16 AM
#6
rabidweasel, i to had a wiring issue at my maf 5 pin mine was casper adapter. i have an 85mm delpi and used my stock pin out for 02 z28 3wire maf 2 wire iat,cross over to an 02 gto maf pin out everything a-ok ecept the iat wired backwards . it's a thermistor and i don't know if flipping the wires would cause malfunction. then i looked at the pcm pinout of the red block and noticed that each wire had a specific pinout number so i guess the pinouts have to be in the correct position ??? rewired to correct and a new maf because the other maf (brand new) was reading -38 degrees with the outside temp being 77 degees . i don't know if iat wire reversal had anything to do with it?? suggestions?? answers?? the oldman....
I am sorry I am not sure what you are talking about with the pcm. I would definitely leave that stock and only modify the new Casper stuff. If you make sure you have the expected signals all the way to the maf/iat it should work.
Whigham you should be able to use hat, no problem. If you want the colors to match just move the pins around on the connector...the main thing is obviously that the wires end up in the correct location...not a big deal at all.
Last edited by therabidweasel; 09-30-2012 at 06:24 AM.
09-30-2012, 09:16 AM
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rabidweasel, i left the pin out in the pcm color correct,as with stock configuration,then i moved the casper harness pins thats when i read high on the new 85/maf/iat. swapped anew one and read current temps, a-ok. so this leads me to believe that it might be pin sensitive. no swap at pcm just the 2 conductors in the adapter harness. are yousaying that a thermistor is not polarized? that the wires are notsensitive to criss/crossing . i found this problem after i ran for a while so i don't know if the iat wasbad to begin with. my mechcanic friend said that maf's are like everything else you could get a new one thats bad. thats my situation. didn't know if pinout caused it or bad maf . so i'm stuck at being befuddled as to witch it was... the oldman....
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09-30-2012, 09:38 AM
#8
It could definitely have had a bad connection internal to the iat. thermistors themselves are definitely not polarized, I am 100% certain. That said, were one of the legs connected to some other part of the circuit through a third wire or the chassis the circuit reading the iat could be polarization sensitive...but since talking a plastic housng with two wires and you were reading off the charts high my bet is a bad connection somewhere.
I don't have a scanner, but if you disconnect the iat completely I would bet it'd read -38.
I don't have a scanner, but if you disconnect the iat completely I would bet it'd read -38.
10-02-2012, 12:18 PM
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i replaced the 85mm maf and it cleared the code and read outside temp correctly and seems to work . i too have an electrical background , not an EE by no means but have a high ammount of respect for them . thanks for your help and input rabidweasel . the oldman..
10-02-2012, 04:15 PM
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BTW Steve, get rid of that POS power steering cooler ASAP before it starts leaking (like mine did) and pissing coolant into your PS fluid and vice-versa!
10-02-2012, 06:41 PM
#11
Rob...wish I would have known that was even possible before I cut that silicone hose for it. Hmm. Thanks for the heads up. I have some tales to tell you btw.
