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CAT 772 ECM loss of signal

Kubak1 ยท 2025-10-22 03:16

Hello, i need a little help with this problem i am having. We rebuild engine on this machine and the machine was sitting outside for like 3 months with no engine in it. Recently we put everything back together and i am having comunication issue with engine ECM. Code is 590-2 and its active in monitor OHT. We checked every connector for oxydation and everything seems clean. Engine light on dash keeps flashing and temp gauge for water temp keeps boucing up and down. Engine will start but keeps shutting down, no throttle response. Thank you for your suggestions. serial number RLB00607

Replies11
  1. #1Nige2025-10-22 03:57

    Do you have access to Cat ET.?

  2. #2Tyler d4c2025-10-22 08:21

    Was the engine dynoed? Had a 336f i think it was do simlar when the engine was dynoed they flashed it with differnet software

  3. #3Nige2025-10-22 08:42

    Good question. When the engine was rebuilt was the Engine ECM interfered with (e.g. flashing new software) in any way.? Which ECM is fussing, the Engine (036) or Machine/Monitor (039)

  4. #4Kubak12025-10-23 01:27

    Hello, no the ECM was not flashed. Nothing with the software was changed. I did plug E.T and strange was the in the ECM were faults with exhaust brake solenoids, but this engine dont have those. So i did search in E.T and found out that serial number of the machine is missing in the ECM, so i did wrote it in. Now there is no faults with the engine brake, but still loss of signal. The fault 590-2 is stored and active in Monitor OHT, which is basicly your dashbord display. Could it be like the ECM was without power for so long that it lost its data somehow?

  5. #5Nige2025-10-23 04:47

    Attached the troubleshooting procedure for 590-2. See how you go with that. Do you have the complete electrical schematic for the truck.?

  6. #6Kubak12025-10-23 15:12

    Thank you. I have access to SIS so i have schematic.

  7. #7pittsburgh cat man2025-10-23 15:40

    I think i would start with ecm connectors on the engine check for corrosion 3 months in the weather could cause a poor connection

  8. #8Nige2025-10-23 15:49

    I think 590-2 is likely to be a Datalink wire(s) somewhere.

  9. #9Kubak12025-10-24 02:24

    Thank you guys, i will check the harness again and clean all connections, maybe i will solve the problem.

  10. #10Nige2025-10-24 04:23

    Use the troubleshooting procedure I posted in conjunction with the electrical schematic. As I said above 590-2 relates to the Datalink so basically you are only chasing a single twisted pair of wires in every affected harness.

  11. #11Kubak12025-10-24 04:56

    Thank you Nige. I will focus on that.