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DTC P0031-O2 Sensor 1/1 Heater Circuit Low: Notes

Fig 1: Sensor 1/1 Heater Circuit - Circuit Diagram
G04853736Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

For a complete wiring diagram, refer to appropriate SYSTEM WIRING DIAGRAMS article.

Possible Causes
(K99) O2 SENSOR 1/1 HEATER CONTROL 
CIRCUIT SHORTED TO GROUND 
O2 SENSOR 
PCM 

Always perform the PRE-DIAGNOSTIC TROUBLESHOOTING PROCEDURE before proceeding.