Cummins j1939 3 pin connector, what gives???

[joeseph666]

Hi DK 'ers,

I am hoping to try and improve the Flash process on a Cummins ecm. I usually see a 3 pin deutsch connector that never seems to work for me on Signature/ISX and later.
The backbone connector.

I'll hook up to it with a Dearborn DPA4+,
connected to a Dearborn Breakout Box (DG-DSUB-BOX) connected to a mating 3 pin deutsch connector (DG-BBCABLE).

This should work!
But it does not.

According to Dearborn, the DPA4+ can optionally provide the 60 ohm bus termination by jumpering pins 3 and 4. I have tried this in both configurations... terminated and not terminated.

Are there other secret switches I must know of?

I know the Cummins translator comes with a "backbone harness."

Thanks (in advance)
Joe

[jctech]

Hi DK 'ers,

I am hoping to try and improve the Flash process on a Cummins ecm. I usually see a 3 pin deutsch connector that never seems to work for me on Signature/ISX and later.
The backbone connector.

I'll hook up to it with a Dearborn DPA4+,
connected to a Dearborn Breakout Box (DG-DSUB-BOX) connected to a mating 3 pin deutsch connector (DG-BBCABLE).

This should work!
But it does not.

According to Dearborn, the DPA4+ can optionally provide the 60 ohm bus termination by jumpering pins 3 and 4. I have tried this in both configurations... terminated and not terminated.

Are there other secret switches I must know of?

I know the Cummins translator comes with a "backbone harness."

Thanks (in advance)
Joe

Your best bet would be to check the resistance betwen J1939+ and J1939- (with the ECM disconnected from the harness) some engines have the resistor fitted in the harness and some do not.

[joeseph666]

Hello Jctech,

I am glad you chimed in...
I watched your youtube video today.
That was Very cool.

If some trucks have j1939 termination, and some do not, how does the Inline 5 deal with that on the backbone connector?

I guess you are saying to disconnect the connector to the ecm... and then do a ohms measurement on the triangle connector's + and -.

Well if I can get the schematics for a bench cable... on those EGR ISX's... I won't need the triangle connector.

Thank You JCTech!!!
For everything you have given us here.

[jctech]

Hello Jctech,

I am glad you chimed in...
I watched your youtube video today.
That was Very cool.

If some trucks have j1939 termination, and some do not, how does the Inline 5 deal with that on the backbone connector?
All trucks have the terminating resistors at each end of the datalink, some are fitted in the engine harness by Cummins and some must be fitted in the chassis harness by the OEM

I guess you are saying to disconnect the connector to the ecm... and then do a ohms measurement on the triangle connector's + and -.
Yes, should be 60 ohm (2x 120 ohm resistors), you will have this at the 9 pin.

Well if I can get the schematics for a bench cable... on those EGR ISX's... I won't need the triangle connector.
Use the search button, the CM871 wiring diagram has been posted before, You need the 4 pin power connector, keyswitch signal and datalink wiring (with resistor)

Thank You JCTech!!!
For everything you have given us here.

I think the thread with the wiring diagrams was called "looking for Cummins wiring diagrams"