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Cat Man
Cat Man, Cat Engine Expert
Category: Medium and Heavy Trucks
Satisfied Customers: 8557
Experience:  I am ASE Master Truck Certified.
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I installed a 2WS Emodel in place of a MXS C-15 in a 2007

Customer Question

I installed a 2WS Emodel in place of a MXS C-15 in a 2007 Freightliner classic. The engine starts and runs and the dash works but it wont communicate with lap top . Yes the MXS ECM did and still does communicate. The 2WS was out of a 2000 Freightliner classic. Everything works just no ECM to lap top communication. And yes I have power and ground at 9 pin. As well as all powers at ECM. I need to know what the difference is in the ECM pin outs on the truck side.
Submitted: 6 months ago.
Category: Medium and Heavy Trucks
Expert:  Cat Man replied 6 months ago.
Thanks for asking your question. I will try and help you out.
The communication wires on an MXS and a 2WS are the same. It should be pins 8 and 9. I believe the position of them may swap at the connector. You may want to try swapping wires 8 and 9.
Please reply back if you need more help or have more questions. I am happy to assist.
Customer: replied 6 months ago.
Wouldn't ET or my prolink communicate regardless of those to wires position because it will communicate with either?
Customer: replied 6 months ago.
Either engine especially the prolink which works on many different engines
Customer: replied 6 months ago.
Do you have wiring pin outs for the 2 engines you can send me?
Expert:  Cat Man replied 6 months ago.
If the wires are swapped it reverses polarity. I can get you the pin outs. Let me get some info together. Be back shortly.
Customer: replied 6 months ago.
Switching the wires made no difference.. Put them back where they were .. Correct?
Expert:  Cat Man replied 6 months ago.
10-4. Did the schematic show the wires in the same location?
Customer: replied 6 months ago.
The Cat display in the dash has no communication either
Customer: replied 6 months ago.
Haven't had a chance to check yet downloading and doing that now
Expert:  Cat Man replied 6 months ago.
10-4. Keep me posted.
Customer: replied 6 months ago.
Wires are in same location. Going to ohm them all from plug to connector
Expert:  Cat Man replied 6 months ago.
I thought they were. Let me know what you find.
Customer: replied 6 months ago.
Didn't ohm them no but it will power up the original ECM. The 2WS ECM is used and came with donor engine. All controls work I have checked Jakes cruise etc.. Is it possible for the ECM to have an Internal error that would prevent it from communicating ? I don't have a breakout harness for ET but am thinking of taking it off and down to the dealer to see if they can communicate with it directly
Expert:  Cat Man replied 6 months ago.
it's possible the ECM may be faulty. It's rare but I have seen it a few times over the years. I would have the dealer test it to be sure.
Customer: replied 6 months ago.
There is no 42 which is 1939 ground or .. The only wires in the plug are A B G F power ground and 1708 wires
Customer: replied 6 months ago.
42 isn't in the ECM plug either
Expert:  Cat Man replied 6 months ago.
That's all that's needed to communicate with et. Power and ground and the two 1708 wires. The 2ws does not use 1939. However there should be a parameter to turn the 1939 on.
Customer: replied 6 months ago.
Suggestions? I know the 1708 is good because it reads the MXS ECM but will not read the 2WS
Expert:  Cat Man replied 6 months ago.
I must suspect the ECM. If all four wires are intact and worked on the MXS. I would want to test the ECM.
Please reply back if you need more help or have more questions. I am happy to assist.
Customer: replied 6 months ago.
ECM bench tested fine.. Now what
Expert:  Cat Man replied 6 months ago.

There has got to be something different in the wiring. Many later model trucks use 120 ohm terminating resisters in the data link wiring. The 2WS did not need this.

I would try running new wires form he diagnostic connector to the ECM. I am sure it will communicate then if it bench tested OK.

Customer: replied 6 months ago.
Configuration issue with the different ECMs
Expert:  Cat Man replied 6 months ago.
I'm not sure I understand. Can you elaborate?
Customer: replied 6 months ago.
CAN inputs in the ECM need to be changed? That's where my thinking is going now.. Didn't that change in the early 2000s
Expert:  Cat Man replied 6 months ago.
I see. Yes I believe it was around 2000.
Expert:  Cat Man replied 6 months ago.
But this should not keep ET from communicating
Customer: replied 6 months ago.
ET does thru a bench harness but not through the truck.
Expert:  Cat Man replied 6 months ago.
I see. Yeah there's something different in the truck wiring. I would run new wires.
Customer: replied 6 months ago.
But the MXS ECM does communicate thru the truck.. I am going to make printouts and recheck everything in the am
Expert:  Cat Man replied 6 months ago.
10-4. Let me know how you make out.
Expert:  Cat Man replied 6 months ago.

Hey I just wanted to see how things were going. Please let me know if you need more help. I am happy to assist. If my information was helpful, please leave a good or higher rating so that I receive credit. Thanks!