Diagnostic Aids

Normal Scan tester voltage varies between .1-1.0 volts while in closed loop. Code 13 sets after 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 - EFI TESTS W/O CODES article in the ENGINE PERFORMANCE Section.

Fig 1: Code 13 Circuit Diagram-O2 Sensor (DOHC Non-Turbo)

Courtesy of ISUZU MOTOR CO.

Fig 2: Code 13 Flow Chart-O2 Sensor (DOHC Non-Turbo)

Courtesy of ISUZU MOTOR CO.