DTC P0139: - O2 Circuit Slow Response (Bank 1, Sensor 2)
WARNING: This page does not describe the selected car, but rather 32 other vehicles, including the 2009 Mercury Mountaineer, 2009 Mercury Milan, 2009 Mercury Mariner, 2009 Mercury Grand Marquis, and 2009 Lincoln Town Car. However, it is still accessible from the selected car via links, so may be relevant.
DTC P0139: - O2 CIRCUIT SLOW RESPONSE (BANK 1, SENSOR 2)
| Description: | The heated oxygen sensor (HO2S) monitor tracks the rate of voltage change during the rise and fall of the HO2S signal. When the rate of voltage change is less than a calibrated value, the powertrain control module (PCM) begins to modify the fuel trim attempting to increase the HO2S voltage switch rate. The DTC sets when the PCM is at the allowable limit or has exceeded an allowable length of time for fuel trim modification, without detecting an acceptable rate of voltage change. | ||
| Possible Causes: |
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| Diagnostic Aids: | Access the HO2S test results from the generic OBD menu to verify the DTC. | ||
| Application | Key On Engine Off | Key On Engine Running | Continuous Memory |
| All | - | - | GO to Pinpoint Test DW . |