P0132

Schematic:

CIRCUIT DESCRIPTION
The wide band Heated Oxygen Sensor (HO2S) measures the amount of oxygen in the exhaust stream more quickly and accurately than the switching style HO2S. The wide range HO2S sensor functions more like an air fuel sensor. The wide band sensor consists of an oxygen sensing cell, an oxygen pumping cell, and a heater. The exhaust gas sample passes through a diffusion gap between the sensing cell and the pumping cell. The Engine Control Module (ECM) supplies a signal voltage to the HO2S and uses this voltage as a reference to the amount of oxygen in the exhaust system. An electronic circuit within the ECM controls the pump current through the oxygen pumping cell in order to maintain a constant signal voltage. The ECM monitors the voltage variation on the signal circuit and attempts to keep the voltage constant by increasing or decreasing the amount of current flow or reversing the direction of the current flow to the pumping cell. By measuring the direction and amount of current required to maintain the signal voltage, the ECM can determine the concentration of oxygen in the exhaust. The signal voltage is displayed as a lambda value. A lambda value of 1 is equal to a stoichiometric air fuel ratio of 14.7:1. Under normal operating conditions, the lambda value will remain around 1. When the system is lean, the oxygen level will be high and the lambda signal will be high or more than 1. When the oxygen level is low, the lambda signal will be low or less than 1. The ECM uses this information to maintain the proper air/fuel ratio.

CONDITIONS FOR RUNNING THE DTC
^ Engine at operating temperature
^ The engine speed must be between 1400 and 2400 RPM.
^ Engine load 8-12 percent
^ Mass air flow 18-22 g/s
^ Throttle position 6-10 percent
^ The same bank sensor 2 HO2S diagnosis is completed.
^ No same bank sensor 2 HO2S DTCs present.

CONDITIONS FOR SETTING THE DTC
^ The ECM has determined that the difference between the front and the rear sensor signals is more than expected.
^ The above condition is met for more than 2 seconds.

ACTION TAKEN WHEN THE DTC SETS
The ECM illuminates the Malfunction Indicator Lamp (MIL) and records the operating conditions in the Freeze Frame on the second consecutive drive trip that the diagnostic runs and fails.

CONDITIONS FOR CLEARING THE MIL/DTC
^ The ECM turns OFF the MIL after three consecutive drive trips that the diagnostic runs and passes.
^ A History DTC clears after forty consecutive warm-up cycles in which no failures are reported by this diagnostic or any other emission related diagnostic.
^ The scan tool clears the MIL/DTC.

DIAGNOSTIC AIDS
Use the J 35616-A connector test adapter kit for any test that requires probing the ECM harness connector or a component harness connector.

Check for the following conditions:
^ Inspect for loose or poor ECM grounds.
^ A possible cause for this DTC is an exhaust leak between sensor 1 and sensor 2. Inspect the exhaust system for any leaks.

TEST DESCRIPTION

Steps 1 - 8:

Steps 9 - 17:

The numbers below refer to steps on the diagnostic table.
3. Any exhaust leak, even a small one, can affect the operation of the HO2S. The ECM compares the reading of sensor 1 with the reading from sensor 2 as part of the diagnosis. A leak between sensor 1 and sensor 2 may set a DTC.
9. A short between the signal circuit and the reference ground circuit or the pump current input and output circuits may not appear on the voltage tests. The ECM must be disconnected and each circuit tested for continuity with the other HO2S circuits.