These 46 diagnostic trouble codes share one detection mechanism and one repair path, which is why MechanicDB groups them into a single authored fault family rather than repeating the same explanation 46 times.
| Code | Definition | Repair coverage |
|---|---|---|
| U3549 | Hydrogen Tank High Pressure Sensor 1 Circuit | 4 ranked fixes |
| U354A | Hydrogen Tank A Temperature Sensor 1 Circuit | 4 ranked fixes |
| U354B | Hydrogen Tank A Temperature Sensor 2 Circuit | 4 ranked fixes |
| U354C | Hydrogen Tank B Temperature Sensor 1 Circuit | 4 ranked fixes |
| U354D | Hydrogen Tank B Temperature Sensor 2 Circuit | 4 ranked fixes |
| U354E | Hydrogen Tank C Temperature Sensor 1 Circuit | 4 ranked fixes |
| U354F | Hydrogen Tank C Temperature Sensor 2 Circuit | 4 ranked fixes |
| U3550 | Hydrogen Tank A Valve Control Circuit | 4 ranked fixes |
| U3551 | Hydrogen Tank A Valve Enable Circuit | 4 ranked fixes |
| U3552 | Hydrogen Tank A Valve Performance | 4 ranked fixes |
| U3553 | Hydrogen Tank B Valve Control Circuit | 4 ranked fixes |
| U3554 | Hydrogen Tank B Valve Enable Circuit | 4 ranked fixes |
| U3555 | Hydrogen Tank B Valve Performance | 4 ranked fixes |
| U3556 | Hydrogen Tank C Valve Control Circuit | 4 ranked fixes |
| U3557 | Hydrogen Tank C Valve Enable Circuit | 4 ranked fixes |
| U3558 | Hydrogen Tank C Valve | 4 ranked fixes |
| U3559 | Air Inlet Pressure Sensor Circuit | 4 ranked fixes |
| U355A | Charge Air Cooler Outlet Pressure Sensor 1 Circuit | 4 ranked fixes |
| U355B | Charge Air Cooler Outlet Pressure Sensor 2 Circuit | 4 ranked fixes |
| U355C | Charge Air Cooler Outlet Temperature Sensor Circuit | 4 ranked fixes |
| U355D | Expander Inlet Pressure Sensor 1 Circuit | 4 ranked fixes |
| U355E | Expander Inlet Pressure Sensor 2 Circuit | 4 ranked fixes |
| U355F | Cathode Backpressure Valve Control Circuit | 4 ranked fixes |
| U3560 | Cathode Backpressure Valve Position Sensor Circuit | 4 ranked fixes |
| U3561 | Cathode Bypass Valve Control Circuit | 4 ranked fixes |
| U3562 | Cathode Bypass Valve | 4 ranked fixes |
| U3563 | Cathode Bypass Valve Position Sensor Circuit | 4 ranked fixes |
| U3564 | Hydrogen Supply Line A Pressure Sensor 1 Circuit | 4 ranked fixes |
| U3565 | Hydrogen Supply Line A Pressure Sensor 2 Circuit | 4 ranked fixes |
| U3566 | Anode Inlet Pressure Sensor 1 Circuit | 4 ranked fixes |
| U3567 | Anode Inlet Pressure Sensor 2 Circuit | 4 ranked fixes |
| U3568 | Anode Multifunction Valve Control Circuit | 4 ranked fixes |
| U3569 | Anode Multifunction Valve | 4 ranked fixes |
| U356A | Anode Drain Valve Control Circuit | 4 ranked fixes |
| U356B | Anode Drain Valve | 4 ranked fixes |
| U356C | Anode Header Drain Valve Control Circuit | 4 ranked fixes |
| U356D | Anode Header Drain Valve | 4 ranked fixes |
| U356E | Anode Drain Valve Heater Relay Control Circuit | 4 ranked fixes |
| U356F | Anode Header Drain Valve Heater Relay Control Circuit | 4 ranked fixes |
| U3570 | Stack Inlet Coolant Temperature Sensor Circuit | 4 ranked fixes |
| U3571 | Stack Outlet Coolant Temperature Sensor 1 Circuit | 4 ranked fixes |
| U3572 | Stack Outlet Coolant Temperature Sensor 2 Circuit | 4 ranked fixes |
| U3573 | Coolant Mixing Valve Control Circuit | 4 ranked fixes |
| U3574 | Coolant Mixing Valve | 4 ranked fixes |
| U3575 | Coolant Mixing Valve Position Sensor Circuit | 4 ranked fixes |
| U3576 | Stack Differential Pressure Sensor Circuit | 4 ranked fixes |
This page publishes the fault mechanism and the code index. The licensed dataset adds, for every one of the 15,886 codes, the full authored repair set (56,729 procedures in total) with the fields deliberately withheld here:
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