GM Service Manual Online
For 1990-2009 cars only

DTC P0132 or P0152 California W/ RPO LU3

Circuit Description

The heated oxygen sensor (HO2S) is a sensor designed to create a voltage relative to the oxygen content in the engine exhaust stream. The control module supplies the HO2S with signal high and low circuits. Ignition voltage and ground are supplied to the HO2S heater by independent circuits. The oxygen content of the exhaust indicates when the engine is operating lean or rich. When the HO2S detects that the engine is operating rich, the signal voltage is high, and decreases the signal voltage as the engine runs learner. This oscillation above and below the bias voltage, sometimes referred to as activity or switching, can be monitored with the HO2S signal voltage.

The HO2S contains heater that is necessary in order to quickly warm the sensor to operating temperature. The heater also maintains the operating temperature during extended idle conditions. The HO2S needs to be at a high temperature in order to produce a voltage. When the HO2S reaches operating temperature, the control module monitors the HO2S bias, or reference, voltage. The control module also monitors the HO2S signal voltage for Closed Loop fuel control. During normal Closed Loop fuel operation, the control module will add fuel, or enrich the mixture, when the HO2S detects a lean exhaust content. The control module will subtract fuel, or lean out the mixture, when the HO2S detects a rich exhaust condition.

This DTC is designed to detect an HO2S voltage that remains high for more than a specified number of seconds during test conditions.

Conditions for Running the DTC

    • DTCs P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0121, P0122, P0123, P0200, P0300, P0401, P0404, P0405, P0440, P0442, P0446, P0452, P0453, P1404 or P1441 are not set.
    • The ignition 1 signal is between 9-18 volts.
    • The fuel tank level remaining is more than 10 percent.
    • The loop status is closed.
    • Intrusive tests are not in progress.
    • Scan tool output controls are not active.

Rich Test Enable

    • The air fuel ratio is between 14.5:1-14.7:1.
    • The throttle position (TP) is between 3-70 percent.

Decel Fuel Cut-off Test Enable

    • Decel fuel cut-off (DFCO) is active.
    • The above condition is met for 5 seconds.

Conditions for Setting the DTC

Rich Test

The HO2S voltage is more than 975 mV for 99 seconds.

Decel Fuel cut-off Test

The HO2S voltage is more than 200 mV for 10 seconds.

Action Taken When the DTC Sets

    • The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
    • The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.
    • The control module commands Open Loop.

Conditions for Clearing the MIL/DTC

    • The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
    • A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
    • A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
    • Clear the MIL and the DTC with a scan tool.

Diagnostic Aids

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

    • Inspect the HO2S electrical connections for evidence of water intrusion--Water present in the connector causes the B+ supply to the heater to bleed over to the signal circuit.
    • Inspect the fuel pressure--The system goes rich if the pressure is too high. The PCM compensates for some increase. If the fuel pressure is too high, a DTC may set. Refer to Fuel System Diagnosis .
    • Inspect for a rich injector--Perform the Injector Balance Test. Refer to Fuel Injector Balance Test with Tech 2 .
    • Inspect for a leaking injector--Refer to Fuel System Diagnosis .
    • Inspect the fuel pressure regulator--Inspect the vacuum line going to the fuel pressure regulator for evidence of fuel. Refer to the Fuel System Diagnosis .
    • Inspect the evaporative emissions (EVAP) canister purge--Inspect the canister for fuel saturation. If the canister is full of fuel, check the canister control and the hoses. Refer to Evaporative Emission Control System Description .
    • Inspect the mass airflow (MAF) sensor--Disconnect the MAF sensor and see if the rich condition is corrected. If the condition is corrected, check for proper installation. If the sensor is correctly installed , replace the sensor. If the sensor is installed backwards, the system goes rich. The plastic portion of the sensor has arrows cast that indicate the proper airflow direction. The arrows must point toward the engine.
    • Inspect the HO2S wires-- An oxygen supply inside the HO2S is necessary for proper operation. The HO2S wires provide the supply of oxygen. Inspect the HO2S wires and connections for breaks or for contamination. Refer to Heated Oxygen Sensor Wiring Repairs in Wiring Systems.
    • Inspect the throttle position (TP) sensor--An intermittent TP sensor output causes the system to go rich, due to a false indication of the engine accelerating. For an intermittent condition, refer to Symptoms - Engine Controls .

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. Monitor the HO2S voltage of the opposite bank sensor. If the voltage activity of the opposite bank sensor is similar to the voltage activity of the suspect sensor, check for rich conditions that would affect both cylinder banks. An opposite bank sensor with normal HO2S voltage activity indicates the suspect HO2S is defective or a rich condition exists only on the suspect HO2S cylinder bank.

  2. An HO2S contaminated by silicon will have a white, powdery deposit on the portion of the HO2S that is exposed to the exhaust stream. The usual cause of silica contamination is the use of unapproved silicon RTV engine gasket material or the use of silicon based sprays or fluids within the engine. If the cause of this contamination is not corrected, the replacement HO2S will also get contaminated.

Step

Action

Values

Yes

No

Schematic Reference: Engine Controls Schematics

1

Did you perform the Diagnostic System Check-Engine Controls?

--

Go to Step 2

Go to Diagnostic System Check - Engine Controls

2

  1. Run the engine until a normal operating temperature is reached.
  2. Use a scan tool in order to monitor the HO2S voltage for the sensor that applies to this DTC.

Is the HO2S voltage fixed at more than the specified value?

975 mV

Go to Step 4

Go to Step 3

3

  1. The condition that set this DTC is not present. This DTC may have been set by one of the following conditions:
  2. •  A signal wire intermittently shorted to voltage
    • Any water intrusion into the HO2S connector
    • A silicon contaminated HO2S
    • An intermittent rich engine condition such as the following:
       - An evaporative emission (EVAP) canister purge condition
       - The engine oil contaminated with fuel
       - An incorrect fuel pressure
       - A leaking fuel pressure regulator
       - Any rich fuel injectors
       - An inaccurate MAF sensor
       - A rich engine condition during DFCO operation
  3. Repair any engine conditions as necessary.

Did you find and correct the condition?

--

Go to Step 10

Go to Diagnostic Aids

4

  1. Turn OFF the ignition.
  2. Disconnect the HO2S connector for the sensor that applies to this DTC.
  3. Turn ON the ignition, with the engine OFF.
  4. Use the scan tool in order to monitor the HO2S voltage for the sensor that applies to this DTC.

Is the HO2S voltage within the specified range?

351-551 mV

Go to Step 5

Go to Step 6

5

  1. The HO2S is detecting a rich exhaust condition or may be contaminated. Check for one of the following conditions:
  2. • Any water intrusion into the HO2S connector
    • Any silicon contamination on the HO2S
    • The engine oil contaminated with fuel
    • An EVAP canister purge condition
    • An incorrect fuel pressure
    • A leaking fuel pressure regulator
    • Any rich fuel injectors
    • An inaccurate MAF sensor
  3. Repair any engine conditions as necessary.

Did you find and correct the condition?

--

Go to Step 10

Go to Step 8

6

  1. Turn OFF the ignition.
  2. Disconnect the PCM connector that contains the HO2S high signal circuit.
  3. Turn ON the ignition, with the engine OFF.
  4. Use a DMM in order to measure the voltage between the PCM connector terminal of the HO2S high signal circuit and ground.

Is the voltage more than the specified value?

20 mV

Go to Step 7

Go to Step 9

7

Important: The sensor may be damaged if the circuit is shorted to a voltage source.

Repair the short to voltage in the HO2S high signal circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 10

--

8

Important: Before replacing a contaminated HO2S, determine and repair the cause of the contamination.

Replace the affected HO2S. Refer to Heated Oxygen Sensor Replacement - Bank 1 Sensor 1 or Heated Oxygen Sensor Replacement - Bank 2 Sensor 1 .

Did you complete the replacement?

--

Go to Step 10

--

9

Replace the PCM. Refer to Powertrain Control Module Replacement .

Did you complete the replacement?

--

Go to Step 10

--

10

  1. Use the scan tool in order to clear the DTCs.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC run and pass?

--

Go to Step 11

Go to Step 2

11

With a scan tool, observe the stored information, Capture Info.

Does the scan tool display any DTCs that you have not diagnosed?

--

Go to Diagnostic Trouble Code (DTC) List

System OK

DTC P0132 or P0152 Federal W/ RPO L35

Circuit Description

The heated oxygen sensor (HO2S) is a sensor designed to create a voltage relative to the oxygen content in the engine exhaust stream. The control module supplies the HO2S with signal high and low circuits. Ignition voltage and ground are supplied to the HO2S heater by independent circuits. The oxygen content of the exhaust indicates when the engine is operating lean or rich. When the HO2S detects that the engine is operating rich, the signal voltage is high, and decreases the signal voltage as the engine runs learner. This oscillation above and below the bias voltage, sometimes referred to as activity or switching, can be monitored with the HO2S signal voltage.

The HO2S contains heater that is necessary in order to quickly warm the sensor to operating temperature. The heater also maintains the operating temperature during extended idle conditions. The HO2S needs to be at a high temperature in order to produce a voltage. When the HO2S reaches operating temperature, the control module monitors the HO2S bias, or reference, voltage. The control module also monitors the HO2S signal voltage for Closed Loop fuel control. During normal Closed Loop fuel operation, the control module will add fuel, or enrich the mixture, when the HO2S detects a lean exhaust content. The control module will subtract fuel, or lean out the mixture, when the HO2S detects a rich exhaust condition.

This DTC is designed to detect an HO2S voltage that remains high for more than a specified number of seconds during test conditions.

Conditions for Running the DTC

    • DTCs P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0117, P0116, P0118, P0121, P0122, P0123, P0200, P0300, P0401, P0404, P0405, P0440, P0442, P0446, P0452, P0453, P1404, or P1441 are not set.
    • The ignition 1 signal is between 9-18 volts.
    • The fuel tank level remaining is more than 10 percent.
    • The loop status is closed.
    • Intrusive tests are not in progress.
    • Scan tool output controls are not active.

Rich Test Enable

    • The air fuel ratio is between 14.5:1-14.7:1.
    • The throttle position (TP) is between 3-50 percent.

Decel Fuel Cut-off Test Enable

    • Decel fuel cut-off (DFCO) is active.
    • The above condition is met for 3 seconds.

Conditions for Setting the DTC

Rich Test

The HO2S voltage is more than 977 mV for 150 seconds.

Decel Fuel Cut-off Test

The HO2S voltage is more than 469 mV for 10 seconds.

Action Taken When the DTC Sets

    • The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
    • The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.
    • The control module commands Open Loop.

Conditions for Clearing the MIL/DTC

    • The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
    • A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
    • A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
    • Clear the MIL and the DTC with a scan tool.

Diagnostic Aids

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

    • Inspect the HO2S electrical connections for evidence of water intrusion--Water present in the connector causes the B+ supply to the heater to bleed over to the signal circuit.
    • Inspect the fuel pressure--The system goes rich if the pressure is too high. The PCM compensates for some increase. If the fuel pressure is too high, a DTC may set. Refer to Fuel System Diagnosis .
    • Inspect for a rich injector--Perform the Injector Balance Test. Refer to Fuel Injector Balance Test with Tech 2 .
    • Inspect for a leaking injector--Refer to Fuel System Diagnosis .
    • Inspect the fuel pressure regulator--Inspect the vacuum line going to the fuel pressure regulator for evidence of fuel. Refer to the Fuel System Diagnosis .
    • Inspect the evaporative emissions (EVAP) canister purge--Inspect the canister for fuel saturation. If the canister is full of fuel, check the canister control and the hoses. Refer to Evaporative Emission Control System Description .
    • Inspect the mass airflow (MAF) sensor--Disconnect the MAF sensor and see if the rich condition is corrected. If the condition is corrected, check for proper installation. If the sensor is correctly installed , replace the sensor. If the sensor is installed backwards, the system goes rich. The plastic portion of the sensor has arrows cast that indicate the proper airflow direction. The arrows must point toward the engine.
    • Inspect the HO2S wires-- An oxygen supply inside the HO2S is necessary for proper operation. The HO2S wires provide the supply of oxygen. Inspect the HO2S wires and connections for breaks or for contamination. Refer to Heated Oxygen Sensor Wiring Repairs in Wiring Systems.
    • Inspect the TP sensor--An intermittent TP sensor output causes the system to go rich, due to a false indication of the engine accelerating. For an intermittent condition, refer to Symptoms - Engine Controls .

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. If the voltage is above the specified value the condition is present.

  2. Jumpering the HO2S low signal circuit to ground is necessary for the PCM to correctly measure the voltage on the HO2S high signal circuit. If the HO2S voltage is within the specified range, the PCM and HO2S high signal circuit are OK.

Step

Action

Values

Yes

No

Schematic Reference: Engine Controls Schematics

1

Did you perform the Diagnostic System Check-Engine Controls?

--

Go to Step 2

Go to Diagnostic System Check - Engine Controls

2

  1. Allow the engine to reach operating temperature.
  2. With a scan tool, observe the HO2S voltage for the sensor that applies to this DTC.

Is the HO2S voltage more than the specified value?

977 mV

Go to Step 4

Go to Step 3

3

  1. Observe the Freeze Frame/Failure Records data for this DTC.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text or as close to the Freeze Frame/Failure Records data that you observed.

Does the DTC fail this ignition?

--

Go to Step 4

Go to Diagnostic Aids

4

  1. Turn OFF the ignition.
  2. Disconnect the HO2S connector for the sensor that applies to this DTC.
  3. Jumper the HO2S low signal circuit terminal on the engine harness side to a known good ground.
  4. Turn ON the ignition, with the engine OFF.
  5. Observe the HO2S voltage with a scan tool.

Is the HO2S voltage within the specified range?

350-550 mV

Go to Step 5

Go to Step 6

5

  1. The HO2S may be detecting a rich exhaust condition or may be contaminated. Check for the following conditions:
  2. • Water intrusion into the HO2S connector
    • Silicone contamination of the HO2S
    • Engine oil contaminated by fuel
    • Incorrect fuel pressure
    • Rich fuel injectors
    • Inaccurate MAF sensor
    • EVAP canister purge condition
  3. Repair any of the above or similar engine conditions as necessary.

Did you find and correct the condition?

--

Go to Step 11

Go to Step 7

6

Important: The sensor may be damaged if the circuit is shorted to a voltage source.

  1. Turn OFF the ignition.
  2. Disconnect the PCM connector that contains the HO2S high signal circuit. Refer to Powertrain Control Module Replacement .
  3. Turn ON the ignition, with the engine OFF.
  4. Test the HO2S high signal circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 11

Go to Step 8

7

Inspect for poor connections at the harness connector of the HO2S. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 11

Go to Step 9

8

Inspect for poor connections at the harness connector of the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 11

Go to Step 10

9

Replace the affected HO2S. Refer to Heated Oxygen Sensor Replacement - Bank 1 Sensor 1 or Heated Oxygen Sensor Replacement - Bank 2 Sensor 1 .

Did you complete the replacement?

--

Go to Step 11

--

10

Replace the PCM. Refer to Powertrain Control Module Replacement .

Did you complete the replacement?

--

Go to Step 11

--

11

  1. Use the scan tool in order to clear the DTCs.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC run and pass?

--

Go to Step 12

Go to Step 2

12

With a scan tool, observe the stored information, Capture Info.

Does the scan tool display any DTCs that you have not diagnosed?

--

Go to Diagnostic Trouble Code (DTC) List

System OK