Possible cause

• Connector terminal disconnection, poor contact, damage, deformation, corrosion
• Open circuit in wiring harness between connectors C-72, C-73 and connector C-16
• Open circuit in wiring harness between connector C-16 and connector C-19
• Open circuit in wiring harness between connector C-19 and branch B
• Connectors C-72, C-73 malfunction
• Connector C-16 malfunction
• Connector C-19 malfunction

System wiring diagram

Fig 1: TCM Module Communication Diagram

Courtesy of MAZDA MOTORS CORP.