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Q: Failure to connect to scan tool

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So I had to fix some stuff did a mod but I need to get my obc off limp mode by ckearing check engine light. My cluster is bad though I think, I'm guessing because my instrument display doesn't work any more besides my gas gauge. The scan tool at AutoZone said failure to connect. Is there anyway to get the codes or check to see if my check engine light went out

A: The first thing you should do is use a test...

The first thing you should do is use a test light to check for power at the OBD II connector. It is also known as the data link connector or DLC. Only one is fused by the number 12 15A fuse on the junction block on the left side of the dash. It is possible another one will have power as well.

  • The pink wire at pin 16 is fused.
  • The pink wire at pin 7 comes from the PCM. It may have power, but I am not certain as the wiring diagram doesn’t give me this information.
  • The violet/brown wire is part of the CAN (computer area network). It shows a positive charge, so I would expect power here.

If you find fuse 12 is blown, replace it and try again. You may need to diagnose the instrument cluster first, as you won’t know if the PCM is actually in limp mode without communication with the PCM through a scanner or the instrument cluster.

It is possible the communication problem is a result of your mods. Whenever we modify a vehicle, we become the engineer. This means you are pretty much on your own when it comes to adverse results from any modification.

The short answer, is there is not a way to get codes without a check engine light or scanner communication. You will need to trouble shoot those first.

If you decide that you need some assistance with this, feel free to contact YourMechanic, as one of our mobile technicians can come to you and help diagnose your Check Engine Light firsthand.

Good luck!

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