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DTC P0131: HEATED OXYGEN SENSOR NO. 1 CIRCUIT - LOW VOLTAGE Chevrolet Venture I

Testing & Diagnostics ~167 words

Note. For circuit reference, see WIRING DIAGRAMS article.

Circuit Description

Powertrain Control Module (PCM) supplies about .45 volt to Heated Oxygen Sensor No. 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. DTC will set if PCM detects HO2S 1 voltage is less than predetermined voltage.

For duplication of DTC, ensure

  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 are set.
  2. Closed loop commanded air/fuel ratio is 13.0:1 to 16.5:1.
  3. TP sensor angle is 3-40 percent.
  4. HO2S 1 signal voltage remains less than 175 mV during normal closed loop operation or less than 600 mV during power enrichment mode fuel control operation.

More articles — Engine Controls Self-Diagnostics - 3.4L