Diagnostic Aids

Control module will not go into closed loop if code is set. Code may set if vehicle runs out of fuel or stalls while vehicle is in motion. If oxygen sensor ground becomes loose, a false oxygen sensor reading will occur. This can result in a Code 63 being set. On models equipped with an oxygen sensor heating element, element resistance should be 3.5-14 ohms.

Fig 1: Code 63 Schematic Open Oxygen Sensor Circuit

Fig 2: Code 63 Flow Chart Open Oxygen Sensor Circuit