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Eric, Automotive Repair Shop Manager
Category: Car
Satisfied Customers: 32550
Experience:  Automotive Repair Shop Manager, Technician/JA Mentor
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scion tc: im installing a performance chip to my 2005 scion

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im installing a performance chip to my 2005 scion tc, my friend tried to do it first and cut all the wires, and cut them so short i have to rewire the sensor, what is the color pattern and then what two colors do i wire the chip into.

I will tell you what I tell all my other customers, performance chips are a waste of money and time. I have a huge box filled with these "performance chips" that I have removed from customers cars that have damaged either their MAF/IAT sensor or PCM(powertrain control module) . I have also seen them melt the engine pistons due to leaning the engine out too much.They are snake oil, plain and simple, and dont work. They have been proven time and again by Consumer Reports, Car and Track, MythBusters and others to actually decrease fuel mileage, decrease performance and damage components. the only thing inside that chip is a 25 cent resistor that you could buy at radio shack. That is it. If they worked, every car manufacturer would have added them years ago to met Federal Requirements on gas mileage ratings instead of sinking billions into research or research on increasing HP

Having said that and forewarned you, if you still want to install it: the chip goes to the blue wire(signal) and the red wire(ground)

As far as wire color sequence at the connector:

pin #1 is yellow
Pin #2 is white
Pin #3 is red
Pin #4 is blue
Pin #5 is red

Below is wiring diagram of the MAF/IAT sensor

Customer: replied 4 years ago.

ok i wont install the chip, but i still have to rewire new wire into all the pins, now, the two red wires are confusing because they look exactly the same.


here is connector view:


On the red wires, this is where the fun will come in that you can thank your friend for later.

If you look at the wiring diagram, you will see one red wire goes straight to the ecm(computer) and the other goes to a junction with other red wires from the coolant temp sensor and other sensors.

Ok, the red wire from the computer goes to the #3 pin and the other red one goes to the #5 pin.

you can either trace the red wires to find the one going to the other red wires in a junction to tell which is which, or if you have a voltmeter,

check resistance(OHM setting on voltmeter) between each red wire and the blue wire and let me know and I can look it up and tell you which is which


If you need more help, please use the Reply to Expert button. If you do not require further assistance, at this time please rate my service so I receive credit for my time and services. Thank you

Customer: replied 4 years ago.

well no voltmeter, what about connecting all others, then manually twisting red wires, try to start, if not then switching them. any harm in that?


You can not do that as one is signal and one is a ground. that can blow the maf/iat sensor, which is why I didnt suggest that method.

you will have to either trace the wires or ohm them out with a voltmeter. no way around this that wont blow the sensor
Customer: replied 4 years ago.

ok thanks for your help, one more question, where can i buy another maf meter connector? ive looked everywhere. and you obviously work online, is that a hard field to get into?


that unfortunately a dealer item. your choices are either a dealer or salvage yard to find.

here is a link for becoming a professional at JustAnswer and what is required.

Become a Professional

it depends on your field as to the requirements
Customer: replied 4 years ago.

thanks a billion man, your way easier to talk to then those dumb asses at autozone lol bye


you are welcome and remember, they are just parts salesmen, not techs that have ever wrenched...

please remember to rate service. thanks!
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