P0132

DTC P0132 Heated Oxygen Sensor (HO2S) Circuit High Voltage - Sensor 1 (1 Of 2):

DTC P0132 Heated Oxygen Sensor (HO2S) Circuit High Voltage - Sensor 1 (2 Of 2):

Heated Oxygen Sensor (HO2S) Circuit:

CIRCUIT DESCRIPTION


The Heated Oxygen Sensor (HO2S) produces a voltage that varies between 1OOmV and 9OOmV under normal operating conditions. The Engine Control Module (ECM) monitors this voltage and determines if the exhaust is lean or rich. If the voltage input at the ECM is about 1OOmV the exhaust is lean, and if the voltage input is about 900mV the exhaust is rich. The ECM 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 HO2S 1 voltage remains excessively high for an extended period of time, DTC P0132 will be set.


CONDITIONS FOR RUNNING THE DTC

- Vehicle speed above 32 km/h (20 mph).

- Engine rpm greater than 2000 RPM.

- In closed loop for 20 seconds.

- Barometric pressure greater than 75 kPa.


CONDITIONS FOR SETTING THE DTC


- Minimum voltage is greater than 300mV.

- Maximum voltage average greater than 950mV and minimum voltage average greater than 400mV.

ACTION TAKEN WHEN THE DTC SETS


- The Malfunction Indicator Lamp (MIL) will illuminate after two consecutive ignition cycles in which the diagnostic runs with the fault active.

- The ECM will record operating conditions at the time the diagnostic fails. This information will be stored in the Freeze Frame buffer.


CONDITIONS FOR CLEARING THE MIL/DTC

- The MIL will turn "OFF" after three consecutively passing cycles without a fault present.

- A History DTC will clear after 40 consecutive warm-up cycles without a fault.

- DTC(s) can be cleared by using a scan tool or by disconnecting the ECM battery feed.


DIAGNOSTIC AIDS


Check the following items:

- If DTC's other than Fuel Trim (P0171, P0172), Misfire (P0300 to P0304), EGR (P0400) and HO2S 1 (P0131 to P0134) are set, diagnosis those DTC's first.

- Before replacement of the HO2S, check the HO2S ground circuit for a possible open or short.

- Fuel Pressure. The system will go rich if pressure is too high. The ECM can compensate for some increase. However, if fuel pressure is too high, a DTC P0132 may be set. Refer to Fuel System Diagnosis.

- Check the Evaporative Emissions (EVAP) System Canister for Fuel Saturation. If full of fuel, check canister control and hoses. Refer to Evaporative Emission (EVAP) Control System.

- Check for a leaking fuel pressure regulator diaphragm by checking vacuum line to regulator for the presence of fuel.

- Shorted Heated Oxygen Sensor (HO2S). If the HO2S is internally shorted the HO2S voltage displayed on the scan tool will be over 1 volt. Silicon contamination of the HO2S can also cause a high HO2S voltage to be indicated. This condition is indicated by a powdery white deposit on the portion of the HO2S exposed to the exhaust stream. If contamination is noticed, replace the affected HO2S.

If DTC P0132 cannot be duplicated, the information included in the Freeze Frame data can be useful in determining vehicle operating conditions when the DTC was first set.

If any wiring repairs need to be made, Refer to Repair Procedures in Diagrams.


TEST DESCRIPTION

Number(s) below refer to the step number(s) on the Diagnostic Table.


1. The Engine OBD System Check prompts the technician to complete some basic checks and store the freeze frame data on the scan tool if applicable. This creates an electronic copy of the data taken when the fault occurred. The information is then stored in the scan tool for later reference.

2. Determines if fault is present, vehicle must be at operating temperature.

3. Review Freeze Frame data to determine when the DTC set. Always record this information.