Heavy Equipment Forums Heavy Equipment Community

Cat 725C with code 585-5

Ty817 ยท 2018-02-20 10:55

I have an active code 585-5 Transmission Output Speed Sensor #1 that I need help with. Here's what I did to it so far. I replaced the sensor #1 and #2 (code remains on) I ran direct wires from the sensor #1 and #2 to the Transmission ECM thinking maybe a break in the harness somewhere. The code remains active and I cannot clear it. The voltages from the ECM is reading at 2.5V What do you think I should try next? Any suggestion would be greatly appreciated. Thanks Ty

Replies4
  1. #1Ty8172018-02-20 12:13

    Sorry code 585-8

  2. #2kshansen2018-02-20 19:29

    Tried looking in SIS but one problem is I'm not sure which version of 725C you have appears to be at least a half a dozen different S/N prefixes. At least one I was looking at showed three different speed sensors relating to the power train. Believe on for TC out put and two different transmission out put speed sensors. Are you working on this with Cat ET or just a sevice manual and VOM tester?

  3. #3Ty8172018-02-20 19:46

    I'm working with Cat ET. I don't know what the problem was, but I eliminate the harness. I ran the wires straight from the sensor to the ECM and the code went away. I checked the harness from one end to the other and it was good but I decided to run it direct and it seem to fix the problem.

  4. #4kshansen2018-02-20 20:03

    Could be something like a poor crimp in one of the connectors and when you moved it to test it it made contact but not good enough to make the ECM happy when running. Or on very rare occasion I have found a wire that looked perfect on the out side but the strands of wire inside were broke. "It's always somethin'"