In general the wiring harnesses itself will never get a short or have a open within the harness unless its been in a fire or had mechanical damage done to the harness. Sometimes the harness may experience wire fatigue breakage when the harness is subjected to being constantly flexed back and forth.
The harness connectors sometimes fail due to mechanical damage or they become faulty because of corrosion and rust within the connector itself causing the contact pins to no longer carry a signal to the other modules.
So start by first inspecting the wiring harness and connectors for obvious damage or the connector just being loose. If the connectors and the harness passes the inspection then maybe you have a faulty computer module. But before even doing that make sure the battery and the charging system are good and supplying the proper voltages to the various modules.
Manufacturer Controlled DTC
Control Module
Control Module Improper Shutdown Performance
Vehicle Identification Number
Battery Voltage
Accessory Power Relay
Retained Accessory Power
Control Module Input Power A Circuit/Open
Control Module Input Power B Circuit/Open
Control Module Ground A
Control Module Ground B
Ignition Switch
Ignition Input Accessory/On/Start
Ignition Input Off/On/Start
Ignition Input On/Start
Ignition Input On
Ignition Input Accessory
Ignition Input Start
Ignition Input Off
Control Module Improper Wake-up Performance
Control Module Input Power C Circuit/Open
Control Module Input Power D Circuit/Open
Control Module Ground C
Control Module Ground D
Control Module Timer/Clock Performance
Control Module Input Power Circuit A/B Correlation
Control Module Input Power Circuit B/C Correlation
Control Module Wake-up Circuit A/Open
Control Module Wake-up Circuit A Low
Control Module Wake-up Circuit A High
Control Module Wake-up Circuit A Performance
Control Module Wake-up Circuit B/Open
Control Module Wake-up Circuit B Low
Control Module Wake-up Circuit B High
Control Module Wake-up Circuit B Performance
Ignition Input Accessory/Off
Control Module Input Power Circuit A
Ignition Input On/Start Circuit Correlation
Control Module Input Power Circuit B
Ignition Input On/Start Circuit Correlation
Control Module A Disable Circuit/Open
Control Module A Disable Circuit Low
Control Module A Disable Circuit High
Control Module A Disable Feedback Circuit
Control Module A Disable Feedback Circuit Low
Control Module A Disable Feedback Circuit High
Ignition Output Accessory/On/Start
Ignition Output Off/On/Start
Ignition Output On/Start
Ignition Output On
Ignition Output Accessory
Ignition Output Start
Ignition Output Off
Ignition Output Accessory/Off
Control Module Security Certificate Missing/Invalid
Communication Authentication Key/Certificate Missing/Invalid
Communication Authentication Signal Invalid Data
Communication Authentication Signal Performance
Control Module Input Power A Circuit Range/Performance
Control Module Input Power A Circuit Low
Control Module Input Power A Circuit High
Control Module Input Power A Circuit Intermittent/Erratic
Control Module Input Power B Circuit Range/Performance
Control Module Input Power B Circuit Low
Control Module Input Power B Circuit High
Control Module Input Power B Circuit Intermittent/Erratic
Control Module Input Power C Circuit Range/Performance
Control Module Input Power C Circuit Low
Control Module Input Power C Circuit High
Control Module Input Power C Circuit Intermittent/Erratic
Control Module Cooling Fan Circuit/Open
Control Module Cooling Fan Circuit Low
Control Module Cooling Fan Circuit High
Control Module Cooling Fan Circuit Range/Performance
Control Module Missing Calibration
High Voltage System Interlock Circuit B
High Voltage System Interlock Circuit B Performance
High Voltage System Interlock Circuit B Low
High Voltage System Interlock Circuit B High
High Voltage System Interlock Circuit C
High Voltage System Interlock Circuit C Performance
High Voltage System Interlock Circuit C Low
High Voltage System Interlock Circuit C High
High Voltage System Interlock Circuit D
High Voltage System Interlock Circuit D Performance
High Voltage System Interlock Circuit D Low
High Voltage System Interlock Circuit D High
High Voltage System Interlock Circuit E
High Voltage System Interlock Circuit E Performance
High Voltage System Interlock Circuit E Low
High Voltage System Interlock Circuit E High
High Voltage System Interlock Circuit F
High Voltage System Interlock Circuit F Performance
High Voltage System Interlock Circuit F Low
High Voltage System Interlock Circuit F High
High Voltage System Interlock Circuit G
High Voltage System Interlock Circuit G Performance
High Voltage System Interlock Circuit G Low
High Voltage System Interlock Circuit G High
High Voltage System Interlock Circuit H
High Voltage System Interlock Circuit H Performance
High Voltage System Interlock Circuit H Low
High Voltage System Interlock Circuit H High
High Voltage System Interlock Circuit J
High Voltage System Interlock Circuit J Performance
High Voltage System Interlock Circuit J Low
High Voltage System Interlock Circuit J High
High Voltage System Interlock Circuit K
High Voltage System Interlock Circuit K Performance
High Voltage System Interlock Circuit K Low
High Voltage System Interlock Circuit K High
High Voltage System Interlock Circuit L
High Voltage System Interlock Circuit L Performance
High Voltage System Interlock Circuit L Low
High Voltage System Interlock Circuit L High
High Voltage System Interlock Circuit M
High Voltage System Interlock Circuit M Performance
High Voltage System Interlock Circuit M Low
High Voltage System Interlock Circuit M High
High Voltage System Interlock Circuit N
High Voltage System Interlock Circuit N Performance
High Voltage System Interlock Circuit N Low
High Voltage System Interlock Circuit N High
High Voltage System Interlock Circuit O
High Voltage System Interlock Circuit O Performance
High Voltage System Interlock Circuit O Low
High Voltage System Interlock Circuit O High
High Voltage System Interlock Circuit P
High Voltage System Interlock Circuit P Performance
High Voltage System Interlock Circuit P Low
High Voltage System Interlock Circuit P High
Hydrogen Tank High Pressure Sensor 1 Circuit
Hydrogen Tank A Temperature Sensor 1 Circuit
Hydrogen Tank A Temperature Sensor 2 Circuit
Hydrogen Tank B Temperature Sensor 1 Circuit
Hydrogen Tank B Temperature Sensor 2 Circuit
Hydrogen Tank C Temperature Sensor 1 Circuit
Hydrogen Tank C Temperature Sensor 2 Circuit
Hydrogen Tank A Valve Control Circuit
Hydrogen Tank A Valve Enable Circuit
Hydrogen Tank A Valve Performance
Hydrogen Tank B Valve Control Circuit
Hydrogen Tank B Valve Enable Circuit
Hydrogen Tank B Valve Performance
Hydrogen Tank C Valve Control Circuit
Hydrogen Tank C Valve Enable Circuit
Hydrogen Tank C Valve
Air Inlet Pressure Sensor Circuit
Charge Air Cooler Outlet Pressure Sensor 1 Circuit
Charge Air Cooler Outlet Pressure Sensor 2 Circuit
Charge Air Cooler Outlet Temperature Sensor Circuit
Expander Inlet Pressure Sensor 1 Circuit
Expander Inlet Pressure Sensor 2 Circuit
Cathode Backpressure Valve Control Circuit
Cathode Backpressure Valve Position Sensor Circuit
Cathode Bypass Valve Control Circuit
Cathode Bypass Valve
Cathode Bypass Valve Position Sensor Circuit
Hydrogen Supply Line A Pressure Sensor 1 Circuit
Hydrogen Supply Line A Pressure Sensor 2 Circuit
Anode Inlet Pressure Sensor 1 Circuit
Anode Inlet Pressure Sensor 2 Circuit
Anode Multifunction Valve Control Circuit
Anode Multifunction Valve
Anode Drain Valve Control Circuit
Anode Drain Valve
Anode Header Drain Valve Control Circuit
Anode Header Drain Valve
Anode Drain Valve Heater Relay Control Circuit
Anode Header Drain Valve Heater Relay Control Circuit
Stack Inlet Coolant Temperature Sensor Circuit
Stack Outlet Coolant Temperature Sensor 1 Circuit
Stack Outlet Coolant Temperature Sensor 2 Circuit
Coolant Mixing Valve Control Circuit
Coolant Mixing Valve
Coolant Mixing Valve Position Sensor Circuit
Stack Differential Pressure Sensor Circuit