NOTE: The 1993–95, rear-wheel drive 2.4L (California)
Pick-ups have the same engine controls as the 3.0L engines. All other 2.4L engines
are listed as 2.4L engines.
- Before testing, warm the engine to normal operating temperature. Coolant
temperature must be 80–85°C (175–185°F) or more.
NOTE: An accurate digital voltmeter is required for this
test.
- Shut the engine off. Disconnect the oxygen sensor connector and connect
the positive probe of the voltmeter to the sensor connector.
- Ground the negative probe of the meter to the body or the engine as convenient
but do not ground it back to the sensor or connect it to the second terminal.
- Place the meter where it can be seen from the driver's seat. Start the engine.
- Race the engine to about 4000 rpm and observe the meter; it should show
about 1 volt (600–1000 mV).
- Shut the engine off, remove the test equipment and reconnect the sensor
harness.
- If the sensor does not show this value, replace it with a new one.
- Unplug the connector to the O2sensor, then use the test harness (Mitsubishi
MD998464) to link the connector and the sensor together.
- Check that there is continuity between terminal 1 (black clip of the test
harness) and terminal 3 (white clip) of the O2sensor connector. There should
be approximately 20 ohms at 68°F (20°C).
- If there is no continuity, replace the O2sensor.
- Warm the engine until the coolant temperature is 176°F (80°C)
or higher.
- Using jumper wires, connect terminal 1 (black clip) and terminal 3 (white
clip) of the O2sensor with the positive battery terminal and negative battery
terminal respectively.
WARNING
When connecting the jumper wires, be careful not to connect them to the
wrong terminals, since this could damage the O2sensor. The terminals should
be terminal 1 (+) and terminal 3 (-).
- Connect a digital voltmeter to terminal 2 (red clip) and terminal 4 (blue
clip).
- While repeatedly racing the engine, measure the O2sensor's output voltage.
The voltage should measure between 0.6–1.0 volts.
- If the measurements are not as specified, the cause is probably a malfunction
of the O2sensor.
