RAM 3500 Truck 2WD V10-8.0L VIN W MDC (1999)
Oxygen Sensor: Testing and Inspection
To perform a complete test of the O2S sensors and their circuitry, refer to the DRB scan tool and appropriate Powertrain Diagnostics Procedures. To test
the O2S sensors only, refer to the following.
A total of 4 oxygen sensors (left, right, pre-catalyst and post catalyst) are used with the 8.0L engine when equipped with the Medium Duty Emission
Cycle (MDC) engine package.
Only 2 oxygen sensors (left and right) are used with the 8.0L engine when equipped with the Heavy Duty Emission Cycle (HDC) engine.
Pre-Catalyst/Post Catalyst Oxygen Sensor Locations
The pre-catalyst O2S sensor is located on the inlet end of the catalytic converter.
The post catalyst O2S sensor is located on the outlet end of the catalytic converter.
Left/Right Oxygen Sensor Locations
The left and right sensors are located on the left and right exhaust downpipes.
Each O2S heating element can be tested with an ohmmeter as follows:
Disconnect the O2S sensor connector. Connect the ohmmeter test leads across the white wire terminal of the sensor connector. Resistance should be
between 4.5 ± 0.5 ohms and 7 ohms. Replace the sensor if the ohmmeter displays an infinity (open) reading.
