Oxygen Sensor Readings

Monitoring O2 readings

We have to thank DSM for putting an O2 sensor wire in the passenger compartment. It's located behind the kickpanel on the passenger side under the dash. It's taped up to the set of wiring harnesses and is a single wire with a female spade connector end (not connected to anything). This wire is the positive feed from the O2 sensor. You can grab the ground from any metal point, be sure not to touch the positive wire to the ground while the car is running.

To get to the sensor wire you have to remove the vent (black plastic thing under dash) and the side kick panel. You can see the wiring harnesses on the right side of the picture with the blower motor for reference (far right picture)

Here are 3 pictures showing how to find the O2 sensor monitoring wire. It's taped to the wire loom way up underneath towards the front of the car. You can use a standard crimp type male connector to plug into the wire. Don't even try splicing it, it's way out of the way and you will have a hard time just trying to wrap tape around it. You can pick up the ground from anywhere in the car to hook up to the ground on your voltmeter.

The O2 sensor will give various readings all between 0 and 1 Volt. The closer to 1 Volt the richer the engine condition. Any value below .6Volts indicates a really lean operating condition.

There are 3 different sets of readings you will get:

Idle - Voltage will fluctuate between .1 and .95 volts, this is totally normal as the computer is always playing with the mixture.
Accelerating - Voltage should stay above .88
Decelerating - Voltage will drop since little or no fuel is being delivered. 0-.2 volts is normal with some .85 spikes

If you aren't getting any readings higher than .6 volts chances are your oxygen sensor is fouled and needs replacing. Unfortunately there is no way to clean an O2 sensor.

You can take the readings from the O2 sensor harness if you suspect you may have a short which is causing your low readings, the sensor doesn't need voltage from the battery to produce a reading since the heated exhaust gas is creating the energy which is converted to electric energy (dc volts).

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This page was last edited July 27, 2001 10:27 PM