RAM 3500 Truck 2WD V10-8.0L VIN W HDC (2000)
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 sensor also provides an input to determine catalytic convertor efficiency.
Upstream Sensors (California Emissions)
Two upstream sensors are used (1/1 and 2/1). The 1/1 sensor is the first sensor to receive exhaust gases from the #1 cylinder. They provide an
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.
Medium and Heavy Duty 8.0L V-10 Engine
Four oxygen sensors are used (2 upstream, 1 pre-catalyst and 1 post-catalyst). The upstream sensors (1/1 and 2/1) will fine-tune the air-fuel
ratio through the Powertrain Control Module (PCM). The pre-catalyst (1/2) and post-catalyst (1/3) sensors will determine catalytic convertor
efficiency (efficiency of the main catalytic convertor). This is also done through the PCM.
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.
