DTC P1138: Lack of HO2S-12 Switch, Sensor Indicates Rich
WARNING: This page does not describe the selected car, but rather 32 other vehicles, including the 2005 Mercury Sable, 2005 Mercury Mountaineer, 2005 Mercury Monterey, 2005 Mercury Montego, and 2005 Mercury Mariner. However, it is still accessible from the selected car via links, so may be relevant.
P1138 - LACK OF HO2S-12 SWITCH, SENSOR INDICATES RICH
| Description: | The downstream heated oxygen sensor (HO2S) is forced rich and lean and monitored by the powertrain control module (PCM). The test fails if the PCM does not detect the output of the HO2S in a calibrated amount of time. | ||
| Possible Causes: |
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| Diagnostic Aids: | |||
| Application | Key On Engine Off | Key On Engine Running | Continuous Memory |
| All | - | GO to H: Fuel Control STEP H49. | - |