When this code triggers, the forklift’s Engine Control Unit (ECU) is trying to protect the engine from damage. You will likely observe the following symptoms:
In worst-case scenarios, the internal CAN transceiver chip inside the traction controller (ZAPI or Curtis) fails. This is a hardware failure requiring controller replacement or board-level repair. hyster forklift fault code 3701-15
If the fault code advances to , the forklift will no longer allow a manual parked regeneration. At that stage, a technician must use a PC Service Tool to force a regeneration. If it reaches 3701-0 , the DPF is likely "baked" and must be removed for professional cleaning or replacement. When this code triggers, the forklift’s Engine Control