RAM 2500 Truck 4WD V8-5.2L VIN Y (2000)
input voltage to the PCM. The input tells the PCM the oxygen content of the exhaust gas. The PCM uses this information to fine tune fuel
delivery to maintain the correct oxygen content at the downstream oxygen sensors. The PCM will change the air/fuel ratio until the upstream
sensors input a voltage that the PCM has determined will make the downstream sensors output (oxygen content) correct.
The upstream oxygen sensors also provide an input to determine mini-catalyst efficiency. Main catalytic convertor efficiency is not calculated
with this package.
Downstream Sensors (California Emissions)
Two downstream sensors are used (1/2 and 2/2). The downstream sensors are used to determine the correct air-fuel ratio. As the oxygen
content changes at the downstream sensor, the PCM calculates how much air-fuel ratio change is required. The PCM then looks at the
upstream oxygen sensor voltage, and changes fuel delivery until the upstream sensor voltage changes enough to correct the downstream sensor
voltage (oxygen content).
The downstream oxygen sensors also provide an input to determine mini-catalyst efficiency. Main catalytic convertor efficiency is not
calculated with this package.
Engines equipped with either a downstream sensor(s), or a post-catalytic sensor, will monitor catalytic convertor efficiency. If efficiency is
below emission standards, the Malfunction Indicator Lamp (MIL) will be illuminated and a Diagnostic Trouble Code (DTC) will be set. Refer
to Monitored Systems in Emission Control Systems for additional information.
