Diagnostic Aids

Normal scan voltage varies between .1 and 1.0 volt (100-999 mV) while in closed loop. Code 13 will set within one minute if voltage remains between .347 and .547 volt, but system will go into open loop in approximately 15 seconds after Code 13 is set.

Verify ground connections are clean and tight at terminals D6 and D7. An open circuit in these terminals will set a Code 13. If code is intermittent, see TESTS W/O CODES article in this section.

Check O2 sensor wire for induced voltage. Disconnect O2 sensor signal wire at sensor and ECM. Using DVOM, measure voltage on wire with engine running. If .3 volt (300 mV) or more is present, check signal wire shield and/or reroute signal wire away from any high voltage sources (ignition wires, battery cables, alternator "B" circuit, etc.).

Fig 1: Code 13 - Schematic (Storm VIN 8) Heated Oxygen Sensor Circuit, Open Circuit

Fig 2: Code 13 - Flow Chart (Storm VIN 8) Non-Heated Oxygen Sensor Circuit, Open Circuit