37MGRA EH b3 (Communication Malfunction Between Wire and Master Control) Diagnosis and Solution

Diagnostic codes covered

EH B3

Description: If Indoor PCB does not receive feedback from wired controller, the error displays on the wired controller Recommended parts to prepare: Connection wires, Indoor PCB, Wired controller

Troubleshooting workflow

EH b3 (Communication Malfunction Between Wire and Master Control) Diagnosis and Solution workflow — EHb3 (Communication Malfunction Between Wire and Master Control) Diagnosis and Solution workflow

Workflow source: original 37MGRA-02SM service-manual PDF. Error-code names cross-checked against 37MGRA-04SI.