P0131 HO2S Circuit Low Voltage Bank 1 Sensor 1
P0132 HO2S Circuit High Voltage Bank 1 Sensor 1
- I don't have a listing for P1751.
- I know you have already changed the B2S1 O2 sensor. Before replacing the B1S1, check the connections. At the sensor, the electrical connector, and at the PCM. Corrosion build up could also cause these issues. If nothing is found, stick a new B1S1 sensor in there and see what happens. See the wire diagram and diag chart below:
The powertrain control module (PCM) supplies a bias voltage of about 450 mV between the heated oxygen sensor (HO2S) signal and low circuits. When measured with a 10 megaohm digital voltmeter, this may display as low as 320 mV . The oxygen sensor varies the voltage within a range of about 1000 mV when exhaust is rich, down through about 10 mV when exhaust is lean. The PCM constantly monitors the HO2S signal during "closed loop" operation and compensates for a rich or lean condition by decreasing or increasing injector pulse width as necessary. If the Bank 1 HO2S 1 voltage remains excessively high for an extended period of time, DTC P0132 will be set.
Conditions for Setting the DTC
- No related DTCs.
- Engine coolant temperature is above 60 °C (140 °F)
- "Closed loop" commanded air/fuel ratio is between 14.5 and 14.8.
- Bank 1 HO2S 1 signal voltage remains above 952 mV during normal "closed loop" operation for a total of 77 seconds over a 90-second period. OR
- Bank 1 HO2S 1 signal voltage remains above 500 mV during "deceleration fuel cutoff mode" operation for 3 seconds .
Action Taken When the DTC Sets
- The PCM will ON the MIL after second trip with detected fault.
- The PCM will store conditions which were present when the DTC was set as Freeze Frame and in the Failure Records data.
- "Open loop" fuel control will be in effect.
Conditions for Clearing the MIL/DTC
- The PCM will turn the MIL "OFF" on the third consecutive trip cycle during which the diagnostic has been run and the fault condition is no longer present.
- A history DTC P0132 will clear after 40 consecutive warm-up cycles have occurred without a fault.
- DTC P0132 can be cleared by using the Tech 2 "Clear Info" function or by disconnecting the PCM battery feed.
Check the following items:
- Fuel pressure - The system will go rich if pressure is too high. The PCM can compensate for some increase. However, if fuel pressure is too high, a DTC P0132 may be set. Refer to Fuel System Diagnosis.
- Perform "Injector Balance Test" - Refer to Fuel System Diagnosis.
- Check the EVAP canister for fuel saturation - If full of fuel, check canister control and hoses. Refer to Evaporative (EVAP) Emission Control System .
- MAF sensor -The system can go rich if MAF sensor signal indicates an engine airflow measurement that is not correct. Disconnect the MAF sensor to see it the rich condition is corrected. If so, replace the MAF sensor.
- Check for a leak in the fuel pressure regulator diaphragm by checking the vacuum line to the regulator for the presence of fuel. There should be no fuel in the vacuum line.
- An intermittent TP sensor output will cause the system to go rich due to a false indication of the engine acceleration.
- Shorted Heated Oxygen Sensor (HO2S) -If the HO2S is internally shorted, the HO2S voltage displayed on the Tech 2 will be over 1 volt . Try disconnecting the affected HO2S with the key "ON," engine "OFF." If the displayed HO2S voltage changes from over 1000 mV to around 450 mV , replace the HO2S. Silicon contamination of the HO2S can also cause a high HO2S voltage to be indicated. This condition is indicated by a powdery deposit on the portion of the HO2S exposed to the exhaust stream. If contamination is noticed, replace the affected HO2S.
- Open HO2S Signal Circuit or Faulty HO2S-A poor connection or open in the HO2S signal circuit can cause the DTC to set during deceleration fuel mode. An HO2S which is faulty and not allowing a full voltage swing between the rich and lean thresholds can also cause this condition. Operate the vehicle by monitoring the HO2S voltage with a Tech 2. If the HO2S voltage is limited within a range between 300 mV to 600 mV , check the HO2S signal circuit wiring and associated terminal conditions.
- If none of the above conditions are present, replace the affected HO2S.