Heated Oxygen Sensor Monitor
PCM monitors the deteriorated condition of the front heated oxygen sensor by checking the lean/rich switching frequency of the heated oxygen sensor.
The PCM checks the output voltage of the rear heated oxygen sensor in order to monitor whether the heated oxygen sensor output is stuck.
This monitor applies to DTCs P0132, P0133, P0137, P0138, P0139, P0152, P0153, P0158 and P0159. Following conditions must be met during the test:
- Engine coolant temperature must be 176°F (80°C) or greater.
- Atmospheric temperature is 14°F (-10°C) or greater.
- Selector lever is in "D" range.
Monitor takes about 5 minutes to complete. This cycle must be completed 2 times. Run monitor as shown. See Fig 1 . Remove all test equipment from vehicle and install all components and connectors that were removed or disconnected during testing. Perform steps as follows:
- Start engine and accelerate to 35-40 MPH.
- While keeping accelerator pedal position constant, keep speed at 35-40 MPH for 120 seconds or more (this is when monitor runs).
- Return vehicle to shop and Turn the ignition switch to LOCK position. Recheck for DTCs. If DTC P0132, P0133, P0137, P0138, P0139, P0152, P0153, P0158 or P0159 resets, return to appropriate repair procedure under DIAGNOSTIC TESTS .