Code 157 maf

1slow50

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95 gt, cai, shortys n o/r x pipe. I have replaced the maf n still getting the code 157. Could it b a wiring problem? How would I go about checking that?

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ryclef331

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how long was the CAI on the car before you got the code? If it was a recent thing and the code popped up shortly after, that may be an issue. Check the harness, connector, etc. for cracks, chaffing, shorted out wires. Start with that and report back.
 

1slow50

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I looked over the wires that I could see without digging in the wheel well n stuff. Everything looks good.

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CC'S95GT

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when was the last time the MAF was cleaned.
CAI's with filters that get oiled has a tendancy to deposit oil on the MAF and give bad readings to the computer.
 

1slow50

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I replaced the maf already, I was having the same problem b4 I changed it cuz I thought it was bad. I cleared the codes after I replaced it n came back. How do I test it with a mulimeter? Which wires do I test n what should it read?

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CC'S95GT

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Not sure how to test the MAF.
I do know they are heated.
the wiring diagram in the back of your Haynes/Chilton manual might help out there.
 

Addermk2

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157
(R,M)​
Mass Air Flow signal is/was low or grounded – MAF


94-95_5.0_EEC_Wiring_Diagram.gif



With a DVOM (multi-meter) check continuity from pins 9(TAN/LT BLU) and 50(LT BLU/RED) to their corresponding ends on the maf harness. also, with the main ECU and maf plugs disconnected, check for continuity to ground.
 

1slow50

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now where it says control module, in fact that is the plug goin to the ecu right?? and test pin 9, 50?
 

1slow50

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Yea if u want, that would be great, I'm a back yard mechanic in training lol. I've really never messed wit the electrical system too much. That's y I might ask sum dumb ass ?s I wanna make sure I'm doin it right

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1slow50

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so i tested the voltage at the maf plug wit key on engine off and it was reading 12 volts, so i went further back to the next plug the 1 that comes out of the fender and that tested -5.85. im guessing i have a real problem here. i unpluged the ecu n it has 3 rows of pins, i cant find a pic to show me what pins i should b testing for cont.
 

1slow50

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i been trying to pull sum pics up of the ecu plug to find out which 1s are pin 50 n pin 9, do they go in order? the 1s i have seen go in order starting at the bottom @ #1 up to the top to #60. is that correct? just trying to make sure im checking the continuity in the right pins
 

Addermk2

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i been trying to pull sum pics up of the ecu plug to find out which 1s are pin 50 n pin 9, do they go in order? the 1s i have seen go in order starting at the bottom @ #1 up to the top to #60. is that correct? just trying to make sure im checking the continuity in the right pins

There are numbers on the connector.
 

1slow50

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I test #9 n it was good, the color of the wire changed from the ecu plug to the maf harness. Nothing on #50

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1slow50

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i was able to get a reading from pin 9 but nothing on pin 50. so im trying to track the wire but the colors are throwing me off. its 1 color coming from the ecu plug and a diff color when it gets to the maf harness. when its running n i unplug maf it still runs, no change in idle, same thing when i unplug the iac. when i unplug the tps the idle changes but the rpm's wont hang. when everythings plugged in the it rev's up to 2300 pms n then bogges down n hangs. i have replaced almost everything but tps n iac.
 

1slow50

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Am I gonna have to cut all the tape n wire loom away from all the wires to see where the problem is?

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toyman

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I'm puzzled by the wire color change. That shouldn't be the case. Exactly what colors are you seeing at the MAF that you think are coming from the ECU (PCM). Pin 50 light blue red stripe to ?? and Pin 9 Tan with light blue stripe to ?? at the MAF connector.
 

Addermk2

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I haven't really been following the thread, sorry. I'll update either tonight or tomorrow at some point.
 

1slow50

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Ok so this green/orange wire is coming from pin #9
gere5uqe.jpg



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