Diagnostic Aids

Normal scan tester voltage varies between .1-1.0 volt while in closed loop. Code 13 sets in approximately one minute if voltage remains between .35 and .55 volt, but system will enter open loop in approximately 15 seconds. For intermittent inspection, see INTERMITTENTS under TESTS W/O CODES article in the ENGINE PERFORMANCE Section.

Fig 1: Code 13 Schematic - O2 Sensor (Open Circuit)

Courtesy of ISUZU MOTOR CO.

Fig 2: Code 13 Flow Chart - O2 Sensor (Open Circuit)

Courtesy of ISUZU MOTOR CO.