P0137

Diagnostic Chart:

Schematic:

When the Heated Oxygen Sensor (HO2S) sensor 2 reaches approximately 318°C (600°F) it becomes an electrical source that responds to the oxygen content in the exhaust. The PCM produces a bias voltage of approximately 450 millivolts on the oxygen sensor circuit. When the sensor is cold its internal resistance is extremely high; therefore, the PCM recognizes the bias as an open circuit. As the sensor warms up, the internal resistance decreases. When the sensor reaches approximately 318°C (600°F), it starts producing a voltage based on the oxygen content in the exhaust stream. Refer to DTC P0141 for heater circuit operation. P0141

DTC PARAMETERS
DTC P0137 will set if the HO2S sensor 2 voltage is less than 44 mV for 150 seconds.
^ Throttle position is between 8% and 50% for 4 seconds.
^ Engine coolant temperature is greater than 40°C (104°F) for 140 seconds.
^ Air flow is greater than 5.5 grams per second for 140 seconds.
^ DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0171, P0201, P0202, P0203, P0204, P0300, P0301, P0302, P0303, P0304, P0336, P0440, P0442, P0446, P0506, P0507, P0601, P0602 or P1441 are not set.

DIAGNOSTIC AIDS
Possible Causes:
If a front O2S DTC and a rear HO2S sensor 2 DTC are set, diagnose the front O2S fault first. A diagnosed front O2S DTC may lead to a mechanical or fuel system failure which set the HO2S sensor 2 DTC.

IMPORTANT: Do not apply grease or any material in the HO2S sensor 2 connector or alter the wiring in any way. The wires carry reference air to the sensor used to determine the difference in oxygen from the exhaust gas to atmosphere.