CAT 740 Dumper

[Nige]

The reason I was asking was because ground connections are notoriously difficult to troubleshoot. A multimeter can show continuity but the wire will not pass the required current for the circuit to operate.

My preference is to use a test lamp of something like 3-5A connected to battery positive to probe ground connections. If the lamp lights brightly then it is passing the rated current and you can be pretty certain that the ground connection is good.

This is only a thought but if the Engine and Transmission ECMs communicate via the CAN and Cat Datalinks I wonder if a power/ground issue on the Engine ECM side could affect the way the Transmission ECM registers “system voltage”.

I think that you would be wise to do the same checks of power & ground on the Engine ECM, even just to rule it out as being anything related to the problem.

 

[ahart]

Are you able to do a transmission fill calibration on this machine? Also, have you checked the harness code plug and continuity from it back to the transmission ECM? I think we need to see if some of these codes can be resolved with their diagnostic procedure.

 

[Chrisso]

Pretty sure Transmission Fill Calibration will just abort with active codes, but worth a shot.

The harness code plug is an input to the Transmission ECM. Is the Transmission ECM getting the right information? Ahart is right, get onto the 650-5 code first.

i have tack out Transmission ECM and conect saperet Transmission ECM to ET stil showing battery volttage unvelable

Also, when you swapped over the transmission ECM from another machine, did the 650-5 & 718-13 codes go away?

I can't tell from the image you posted which ECM you're seeing the "battery voltage - unavailable" on. I wouldn't focus on this yet. Could be normal.

The Transmission ECM sends the following information to the Monitoring System ECM: engine speed, machine ground speed, parking brake switch status, transmission speed selection and service code of the transmission.

So under the Monitoring System ECM in ET, if you can see at least one or two of these readings, the datalink twisted pairs are probably fine.

 

[Nige]

dear

i have tack out Transmission ECM and conect saperet Transmission ECM to ET stil showing battery volttage unvelable

Can you clarify your comment above please.

1. Did you remove the transmission ECM from the machine, apply power to it from an external source, then connect ET to the Datalink Pins.?
2. Or did you remove the Transmission ECM and then install a different ECM in its place on the machine.?

 

[Nige]

Can you possibly connect to the machine and download an Adobe pdf copy of the Product Status Report then post it up here please.?