SR20DET test pipe

[Raymond A. Kawski]

Probe Dude wrote:

> The O2 sensor is a voltage source, using a fixed resistor to ground won't
> work.

Yes but the ECU just monitors the voltage of the line
it sends power to the Rear O2 on.  Adding a resistor, which the
rear o2 is, to the line reduces the voltage.

The 98 ECU has 4 wires for the RearO2 I don't recall how many
are on the pre 98 one.  I think 3.  Heater, Ground and Sensor.

Hook your DVM to the pin on the ECU for the Rear O2 and
check the voltage.

RK