2001 Sterling ecu code 128 and no throttle pedal response

Our 2001 Sterling with 5.9 cummins has been intermittently throwing an ecu code 128, when it does this the throttle pedal goes dead, but it idles fine and has proper oil pressure. It runs good and has good power and no gauges are out of normal when the problem is not occurring.

I've replaced the TPS on the pedal, and I have cleaned the harness plugs on both the pedal harness and the 4 sensors on the coolant tank. I've removed the battery terminals cleaned them and it runs fine for a few weeks then the problem just happened again. Code 128 and the pedal is dead. It seems to act up when it is raining out.

What am I missing?

Any suggestions on what area of the harness, or which particular sensors are most likely to cause this type of intermittent problem?

 

PS

It also recently had a new speed sensor installed by Cummins.

 

Would it help if I posted this in the Freightliner section?