Speedometer not working, ABS & emergency brake light on!

Discussion in 'Chevy Silverado Forum (GMC Sierra)' started by Jeffrey Glen Wicker, Feb 22, 2012.

  1. Jeffrey Glen Wicker

    Jeffrey Glen Wicker New Member

    Hey folks,

    I have just acquired a 2001 1500HD 4x4 (traded my caddy and $500 for it) and the speedo doesn't work. I changed one speed sensor in the transfer case (even swapped them around...for there is two). I took the cluster out of my 2001 2500HD service truck and all other gauges worked except the speedo.

    The truck just recently had the transmission swapped with a working used one from LKQ. I have been looking for disconnected grounds and sensor pig tails to no avail.

    I get the CO236 code on my ABS DTC but that's all the info I can get.

    I am new to the cite and attempted to do a key word search but got nothing useful.

    Please help,

    2001 1500HD 6.0 4x4 AT
    2001 2500HD 6.0 Service truck
  2. Jeffrey Glen Wicker

    Jeffrey Glen Wicker New Member

    Found it. It was a plug in the wrong sensor. The main connection is just a two plug like the rest of the magnetic sensors on the transfer case. I paid 40 bucks on justanswer.com ($29+11 tip...VERY PLEASED) to have a master mechanic talk me through it. CHeck out the conversation here


    I'm for real. Check it out when you get stumped. If it wasn't for his final color code help, I would have wasted all day and still may not have found it before I spent money on a ABS module, or PCM, ignition switch, etc.

  3. dipstick

    dipstick Member 2 Years 100 Posts

    Most times on these chevy trucks if you have a problem will be a bad connection in harness or ignition switch.
  4. Jeffrey Glen Wicker

    Jeffrey Glen Wicker New Member

    Thanks dipstick,

    I will keep an eye out. Getting a crash course on the 6.0 l4q right now. Bought a 2001 2500HD with a bad 6.0 (shredded #1 main bearing) and will pay careful attention to plugs and harnesses in the r&r.


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