When testing or servicing an Oxygen (O2S) sensor you will need to start and
warm the engine to operating temperature in order to either perform the necessary
testing procedures or to easily remove the sensor from its fitting. This will
create a situation in which you will be working around a HOT exhaust
system. The following is a list of precautions to consider during this service:
- Do not pierce any wires when testing an O2S sensor, as this can lead to
wiring harness damage. Backprobe the connector, when necessary.
- While testing the sensor, be sure to keep out of the way of moving engine
components, such as the cooling fan. Refrain from wearing loose clothing that
may become tangled in moving engine components.
- Safety glasses must be worn at all times when working on or near the exhaust
system. Older exhaust systems may be covered with loose rust particles that
can shower you when disturbed. These particles are more than a nuisance and
can injure your eye.
- Be cautious when working on and around the hot exhaust system. Painful burns
will result if skin is exposed to the exhaust system pipes or manifolds.
- The O2S sensor may be difficult to remove when the engine temperature is
below 120°F (48°C). Excessive force may damage the threads in the
exhaust manifold or pipe, therefore always start the engine and allow it to
reach normal operating temperature prior to removal.
- Since O2S sensors are usually designed with a permanently attached wiring
pigtail (this allows the wiring harness and sensor connectors to be positioned
away from the hot exhaust system), it may be necessary to use a socket or
wrench that is designed specifically for this purpose. Before purchasing such
a socket, be sure that you can't save some money by using a box end wrench
for sensor removal.
