DTC P0131 - HO2S CIRCUIT LOW VOLTAGE SENSOR 1 Oldsmobile Cutlass VI

Note. For circuit reference, see the appropriate WIRING DIAGRAMS article. For connector and terminal identification, see CONNECTOR IDENTIFICATION .

Circuit Description

Powertrain Control Module (PCM) supplies about .45 volt to Heated Oxygen Sensor 1 (HO2S 1). The HO2S 1 varies voltage from about one volt when exhaust is rich to about .10 volt when exhaust is lean. PCM monitors and stores sensor voltage information and evaluates the voltage samples to determine amount of time sensor voltage is out of range. If PCM detects HO2S 1 voltage is less than predetermined voltage, DTC will set.

Conditions for setting this DTC are as follows

1. No active misfire, fuel injector circuit, TP sensor, EVAP, IAT sensor MAP, sensor, fuel trim, EGR, ECT sensor, MAF sensor or CKP sensor DTCs set.
2. Closed loop air/fuel ratio is 14.5:1-14.8:1.
3. TP sensor angle is 3-40 percent.
4. HO2S 1 signal voltage remains at less than 300 mV during normal closed loop operation.
5. HO2S 1 signal voltage remains less than 300 mV.
6. Vehicle is operating in power enrichment mode.
7. Conditions present for up to 15 seconds.