Heated Oxygen Sensor (HO2S) Repair

CAUTION:
If the HO2S pigtail wiring, connector or terminal is damaged, the entire HO2S assembly must be replaced.

Never attempt to repair the wiring, connector or terminals of the HO2S.

Use the following guidelines when servicing the HO2S:

1. Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors, the cleaner may get into the sensor and cause poor performance.

2. The sensor pigtail and harness wires should not be damaged in such a way that any of the wires are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems.

3. The sensor or vehicle lead wires should not be sharply bent or kinked. Sharp bends or kinks could block the reference air path through the lead wire.

4. Do not remove or disconnect the HO2S ground wire. Removal of the ground wire will cause poor engine performance.

5. To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector.





NOTE:
Early HO2S harness connectors utilized Econoseal connectors to connect the harness with the HO2S sensor. These connectors had tin plated contacts on all the terminals (see Figure 3). Later 1997 and onwards vehicles utilize Sumitomo connectors which have better latching control and gold plating on the HO2S sensing terminals. Tin plating is still used on the heater terminals of Sumitomo connectors because higher current terminals do not benefit from gold plating on the terminals.