Question about 2004 Chevrolet Tahoe

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Obd 2 connector does not work with any code scanner

I have a 2004 tahoe, runs fine but check engine light came on, and when I hook up to pull codes no scanner will communcate with the truck.....Ive tryed snap-on,auto xray,mac,and the cheapy at auto zone. all say to check the connection or turn ing switch on? ive chased the 4 wires all the way to the firewall then I loose them in the harness, the connector is good.... and I cant find a schematic for the truck anywere. Im a heavy equipment mech and have tryed all I can including pulled the computer and cleaned all connections,checked and cleaned all fuses and harnesses under fuse panels,found no problems.even ran the wiggle test on my auto xray 6000 manualy and shook every dahm wire under the dash and hood? im stumped any help would be great. thanks

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  • michael_m263 Jan 24, 2009

    jonny5846, thanks. I had a car alarm installed and they tapt into the orange wire with a spade splice under the hood fuse box, it cut thru the orange wire and I was not getting full voltage at the connector, since I had the batt disconnected it shut the light off, so I will hook up my scanner and drive to see what codes pop up when the light comes back on. but I am communcating now so thanks again

  • Rick Byrd
    Rick Byrd May 11, 2010

    looks pretty cut and dry , looking at a schematic , pin 16 on aldl goes to cigar fuse under hood fuse block (orange wire) , 99% of the time blown when i don't have communication ... pin 4 = ground (black wire). pin 5 = goes thru a i/p relay block then to ground (black/white wire) , and pin 2 = to a # 205 splice , dataline , left side of dash (purple) . so thats all i see in schematics , hot , ground and data . let me know which 1 is/was the problem .




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HI there....Check to see if the code reader is a CAN OBD 2 code reader. If it is only OBD2 , that may be the problem. In 2003 Some vehicle manufacturers ( ford,Gm,Mazda and Saab) began using a new computer protocol called Controller Area Network (CAN) with the OBD2 and if your vehicle is CAN OBD 2 the simple OBD2 code reader will not work.Contact your local dealer to determine if you vehicle is CAN or not or find a code reader that is CAN OBD2 capable. Hope this helps you out

Posted on Jan 24, 2009

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Glad you got it , hope it didn't take too long to run down the orange wire .

Thanks for using FIX YA !


Posted on Jan 24, 2009


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