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Shift control cat 120h

slevytruck ยท 2023-08-19 07:26

Good day Im having problem with my cat 120h I bought and installed new shift controller due to code 668-2 transmission shift lever. Now the problem its after installed the new part, the engine dont start but with the old one the engine start. I dont know if the new part have to be configurated

Replies12
  1. #1Nige2023-08-19 07:43

    Please can you give the following information: - 1. Machine Serial Number. 2. Part Number of the control you removed. 3. Part Number of the control you installed.

  2. #2slevytruck2023-08-19 08:09

    Hi Thanks for your replay. SN:5fm04594 Part #removed: 253-4019 Part# installed: 452-9831

  3. #3Nige2023-08-19 09:06

    That is an updated Part Number requiring a separate power supply to make it work. Refer to the attached Service Magazine M0114337 detailing the upgrade and Special Instruction M0085139 which gives instructions on how to install the independent power supply.

  4. #4Nige2023-08-21 15:12

    @GEORGIOS198217 - You should download copies of both these documents, because if the electronic transmission shifter control ever fails on your 143H then you will have to do the same upgrade to install a separate power supply to the replacement control.

  5. #5slevytruck2023-08-25 10:29

    Thank you, new power circuit was installed successfully, but the new shift controller have the same code as the old one 668-2 & 764-5 and the computer doesn't read from shift 1 to 5 only reads 6. All wires were check but the problem persist.

  6. #6Nige2023-08-25 10:52

    764-5 is the transmission indicator lamp shorted to ground. Possible cause are the lamp is burned out, a fault in the wiring harness, or the transmission ECM is faulty. Do you have an electrical schematic or access to ET.? I would be interested to know what Part Number of software is in the transmission ECM.

  7. #7slevytruck2023-08-25 11:05
  8. #8Nige2023-08-25 13:02

    That's the latest available software. The 258-5484 contained an update to reduce the number of potential causes of the 668-02 Diagnostic Code. I'm sorry but I am lost at this point. The Code you have indicates that the shift control is bad but that is not logical because the control is new. Apart from trying the new control in a different machine to see if it works I really don't know what to suggest.

  9. #9slevytruck2023-08-25 13:32

    Thank you so much for the assistance we found the problem. A plug was damage

  10. #10Nige2023-08-25 14:18

    Where exactly is that connector located.? It's not the 10-pin marked CONN 15 between the transmission shift console and the machine harness by any chance.?

  11. #11slevytruck2023-08-25 16:58

    Yes thats correct, was the 10-pin CONN15. Plug was replaced and now its working properly, no more active code. Thank you

  12. #12Nige2023-08-25 17:11

    Those Sure-Seal connectors are a pain the the ***. The tools to remove & install the pins can cause injury if not used carefully. Personally I'm glad Cat switched to Deustch connectors.