General Information

OBDII cars have two oxygen sensors to measure the amount of oxygen contained in the exhaust gas. The first sensor is located on the manifold or header and measures O2 content of the exhaust as it escapes from the cylinders. This sensor is used by the PCM/ECM to calculate fuel trims and look for combustion problems. The second oxygen sensor is located after the catalytic converter and is used only to measure catalytic?converter efficiency. The PCM/ECM does NOT use any data from the secondary O2 sensor for engine management. The PCM will set an CEL(check engine light)/SES (service engine soon) / MIL(Malfunction Indicator Lamp) light?if the catalytic converter is removed, the sensor is removed, or the sensor goes bad.

When the test pipe is installed?and the converter is removed??it is necessary to verify that nothing else sets CEL/SES/MIL light and the car can pass OBD emission inspection.?The O2 Sensor Simulator generates proper?sensor? signal? which does?not let the?PCM/ECM to store the error code and set CEL/SES/MIL light.