Diagnostic Aids

Normal Scan tester voltage varies between .1-1.0 volts while in closed loop. Code 13 sets in approximately one minute if voltage remains between 0 and .35 volt, but system will enter open loop in approximately 15 seconds. For intermittent inspection, see INTERMITTENTS in H - TESTING W/O CODE - EFI article.

Fig 1: Code 13: O2 Sensor (Heated Only) Open/Shorted Circuit Diagram

Courtesy of ISUZU MOTOR CO.

Fig 2: Code 13: O2 Sensor (Heated Only) Open/Shorted Flow Chart

Courtesy of ISUZU MOTOR CO.