INACTIVE FAULT CODE 1117/0257

[MLV]

Hello,

Year: 2008
Make: Volvo
Engine: ISX cm871 (de-mandated)

Insite Fault Codes ( Inactive)
1117- Power Supply Lost with Ignition On -Data Erratic, Intermittent, Or Incorrect
0257- Engine Fuel Shutoff Valve Driver- Mechanical System not responding, or out of adjacent

Background:
Driver advised vehicle; at random points in time, will cut out and lose power for couple seconds and kick back on as nothing happened. Driver also advised after vehicle cuts out/loses power, several scenarios may happen. 1 Vehicle starts right back up, 2. The vehicle may not start right back up, but starts couple minutes later, or 3. The vehicle will not start until it cools down- usually several hours later.

To get the vehicle started back up, driver noticed that by unplugging the ECM/plugging back in(1min later), or the couple hours of "Cooldown" will get the vehicle started.

The truck did make it back to our yard and I've been trying to figure out the cause. I had the truck idle from 11am -3pm without any issues. Once we took it our for a spin, the truck started showing symptoms mentioned above. I had the truck plugged in during the test run and noticed every time the vehicle died/cut-out, stalled, I would loose connection to the ECM. Once the truck fires back up, Insite is able to connect to the ECM. I also noticed when truck cuts out and does not start right back up, I would not be able to connect to the ECM ( Insite - Error number :5200 - Lost communication between computer and datalink adapter). In order to get commutation back, you would either wait for hours and hours or unplugging/plugging back in ECM power.


Discovery(What I found)
-Battery terminals damaged/corrosion( rubbing against frame).
- Starter terminals damaged ( Negative/positive were rubbing).
- 9pin connector - pins showing slight corrosion, and/or cracked.
- Wiring Harness inside and outside firewall has some wires that are semi broken or have corrosion. The male and female pins do have corrosion ( not all ).

Question:
1. On the wiring harness, how do I figure out what each wire means/controls/belongs to? Both Volvo and Local cummins dealerships will not provide assistance in identifying the wires.

2. How do I go about repairing the firewall Male/female connectors ( pins) on the wiring harness(Cab).

3. Since starter Positive/Negative terminals made contact, was the ECM damaged/can the ECM get damaged?


4. Replace the wiring harness or repair current one?



Note:
I have pictures ( show/explain current situation better) but Im not sure how to upload them on here.

Any positive feedback or guide will help and is greatly appreciated.