P0132

Circuit Description

The PCM supplies a bias voltage of about 450 mV between the 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 the 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 HO2S 1 voltage remains excessively high for an extended period of time, DTC P0132 will be set.

Conditions for Running the DTC

^ No active TP, MAP, MAF, ECT, IAT, or CKP Sensor, misfire, fuel injector circuit, EVAP, Fuel trim, EGR, DTCs present.
^ System Voltage is greater than 9.0 volts.
^ Closed loop commanded air/fuel ratio is between 14.5 and 14.8.
^ Throttle angle between 3% and 40%.

Conditions for Setting the DTC

^ HO2S 1 signal voltage remains above 975 mV for longer than 45 seconds during normal closed loop operation.
OR
^ HO2S 1 signal voltage remains above 200 mV for longer than 29 seconds during deceleration fuel mode operation.

Action Taken When the DTC Sets

^ The PCM will illuminate the MIL during the second consecutive trip in which the diagnostic has been run and failed.
^ If equipped with traction control, the PCM will command the Electronic Brake and Traction Control Module (EBTCM) via the serial data circuit to turn OFF traction control, and the EBTCM will illuminate the TRACTION OFF lamp.
^ The PCM will store conditions which were present when the DTC set as Freeze Frame and Fail Records data.

Conditions for Clearing the MIL/DTC

^ The PCM will turn the MIL OFF during the third consecutive trip in which the diagnostic has been run and passed.
^ The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
^ The DTC can be cleared by using a scan tool.

Diagnostic Aids

Inspect for 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. Refer to Fuel System Pressure Test. Fuel System Pressure Test
^ Perform Injector Balance Test. Refer to Fuel Injector Balance Test. Component Tests and General Diagnostics
^ Inspect the EVAP Canister for Fuel Saturation. If full of fuel, check canister control and hoses.
^ Disconnect the MAF sensor and see if rich condition is corrected. If so, replace the MAF sensor.
^ Inspect for a leaking fuel pressure regulator diaphragm by checking vacuum line to regulator for the presence of fuel.
^ An intermittent TP sensor output will cause the system to go rich due to a false indication of the engine accelerating.
^ Shorted Heated Oxygen Sensor (HO2S). If the HO2S is internally shorted the HO2S voltage displayed on the scan tool will be over 1.0 volt. Disconnect the affected HO2S and jumper the HO2S low circuit to ground 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 white deposit on the portion of the HO2S exposed to the exhaust stream. If contamination is noticed, replace the affected HO2S.
^ Open HO2S Signal or Low Circuit or Faulty HO2S. A poor connection or open in the HO2S signal or low 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 while monitoring the HO2S voltage with a scan tool. If the HO2S voltage is limited within a range between 300 mV to 600 mV, check the HO2S signal and low circuit wiring and associated terminal connections. If the wiring and connections are OK, replace the HO2S.

Important: Remove any debris from the connector surfaces before servicing a component. Inspect the connector gaskets when diagnosing or replacing a component. Ensure that the gaskets are installed correctly. The gaskets prevent contaminate intrusion.

^ Poor terminal connection.
Inspect the harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and faulty terminal to wire connection. Use a corresponding mating terminal to test for proper tension. Refer to Diagrams.
^ Damaged harness.
Inspect the wiring harness for damage. If the harness appears to be OK, observe the sensor display on the scan tool while moving connectors and wiring harnesses related to the sensor. A change in the sensor display may indicate the location of the fault.
^ Inspect the PCM and the engine grounds for clean and secure connections.

If the DTC is determined to be intermittent, reviewing the Fail Records can be useful in determining when the DTC was last set.

Test Description

The numbers below refer to the step numbers on the Diagnostic Table:

3. DTC P0132 failing during deceleration fuel mode operation may indicate a condition described in the Diagnostic Aids above. If the DTC P0132 test passes while the Fail Records conditions are being duplicated, an intermittent condition is indicated. Reviewing the Fail Records vehicle mileage since the diagnostic test last failed may help determine how often the condition that caused the DTC to be set occurs. This may assist in diagnosing the condition.
7. This vehicle is equipped with a PCM which utilizes an Electrically Erasable Programmable Read Only Memory (EEPROM). When the PCM is being replaced, the new PCM must be programmed.