GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2001 🢒 Cavalier (CNG) 🢒 Engine 🢒 Engine Controls - 2.2L (LN2) 🢒 DTC P0132

Object Number: 621491 Size: SF
Engine Controls Components
Engine Controls Schematics
OBD II Symbol Description Notice
Handling ESD Sensitive Parts Notice
Handling ESD Sensitive Parts Notice

Circuit Description

The oxygen sensor (O2S) is used in order to determine the oxygen content of the engine's exhaust. The oxygen content of the exhaust indicates when the engine is operating lean or rich. When the engine is operating lean the exhaust will have more oxygen content. Once at operating temperature, the O2S will produce a voltage in relation to the oxygen content of the exhaust. The O2S requires an operating temperature of 360°C (600°F) to produce voltage. The O2S will produce more voltage when the exhaust is rich and less voltage when the exhaust is lean. The O2S operating voltage range is around 0.10 volts (100  mV) to 1 volt (1000  mV).

The gasoline control module (VCM / PCM or ECM) supplies a bias (or reference) voltage to the HO2S. This bias voltage is around 450 millivolts.

This DTC is used to indicate an O2S signal voltage that is above the normal operating range of the sensor.

Conditions for Running the DTC
    • The engine is operating on alternative fuel.
    • Engine speed is greater than 500 RPM.
    • Engine coolant temperature is above 70°C (160°F).
    • The AF ECU determines the O2S has been at operating temperature for at least 2 minutes. The engine coolant temperature must be greater than 40°C (104°F) AND the calculated mass air flow must be above 6  grams per second for 2 minutes in order for the AF ECU to determine the O2S is at operating temperature.
    • The AF ECU is operating in Closed Loop fuel control.

Conditions for Setting the DTC

The AF ECU monitors an O2S signal voltage of greater than 1 volt (1000 mV) for 3 seconds continuously.

Action Taken When the DTC Sets

The AF ECU will operate in Open Loop fuel control.

    • A first failure of this DTC will NOT illuminate the MIL and will store as Last Test Failed but not as History.
    • The AF ECU will illuminate the MIL and store the DTC as History after TWO consecutive drive trips that the diagnostic runs and fails.
    • The AF ECU will record operating conditions at the time the DTC sets. This information will be stored as Freeze Frame data.

Conditions for Clearing the MIL/DTC

    • The Last Test Failed status will clear when the DTC runs and passes.
    • The AF ECU will turn OFF the MIL after 3 consecutive drive trips that the DTC runs and passes.
    • The History status will clear after 40 consecutive WARM-UP cycles with NO failures of ANY DTC.
    • All DTC Information can be cleared using a scan tool.
    • Interruption of Control Module (AF ECU / VCM / PCM or ECM) power or ground MAY clear DTC Information. Clearing DTC Information with this method is inconsistent and should not be performed.

Diagnostic Aids

Intermittent Condition

A fault not present indicates the condition that caused the DTC to set is intermittent and not currently present. Refer to Intermittent Conditions diagnostic information located in Symptoms-Engine Controls. If any additional DTCs were stored, proceed to the applicable DTC table in the order stated in the Diagnostic System Check - Alternative Fuels (Engine Controls) .

Test Description

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

  1. An O2S contaminated by silicon will have a white, powdery deposit on the portion of the O2S that is exposed to the exhaust stream. The usual cause of silica contamination is the use of un-approved 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 O2S will also get contaminated.

    2.

  2. An O2S contaminated by silicon will have a white, powdery deposit on the portion of the O2S that is exposed to the exhaust stream. The usual cause of silica contamination is the use of un-approved 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 O2S will also get contaminated.

Step

Action

Value(s)

Yes

No

1

Did you perform the Alternative Fuels Engine Controls Diagnostic System Check?

--

Go to Step 2

Go to Diagnostic System Check - Alternative Fuels (Engine Controls)

2
  1. Run the engine until normal operating temperature is reached.
  2. Using a scan tool establish communication with the AF ECU.
  3. Using a scan tool monitor the AF ECU O2S voltage for the sensor that applies to this DTC.

Is the O2S voltage fixed greater than the value specified?

1  V

Go to Step 5

Go to Step 3

3

The condition that set this DTC is not present. This DTC may have been set by one of the following conditions:

    • A signal wire intermittently shorted to voltage
    • O2S connector water intrusion
    • A silicon contaminated O2S
    • An intermittent rich engine condition such as the following:
       - EVAP canister purge system malfunction
       - Gasoline contaminated engine oil
       - Incorrect fuel pressure
       - A leaking gasoline fuel pressure regulator
       - Rich GMS/MCV
    • Repair any of the above or similar engine conditions as necessary.

Was a condition found and repaired?

--

Go to Step 15

Go to Step 4

4

The fault is not present. Refer to Diagnostic Aids.

Are any DTCs stored that have not been diagnosed?

--

Go to Diagnostic Trouble Code (DTC) List

Go to Intermittent Conditions

5
  1. Run the engine until normal operating temperature is reached.
  2. Using a scan tool establish communication with the gasoline control module (VCM/PCM or ECM).
  3. Using a scan tool monitor the O2S voltage for the sensor that applies to this DTC.

Is the O2S voltage fixed greater than the value specified?

1 V

Go to Step 6

Go to Step 12

6
  1. Turn the ignition OFF.
  2. Disconnect the AF ECU connectors.
  3. Run the engine until normal operating temperature is reached.
  4. Using a scan tool monitor the O2S voltage for the sensor that applies to this DTC.

Is the O2S voltage fixed greater than the value specified?

1 V

Go to Step 7

Go to Step 11

7
  1. Turn the ignition OFF.
  2. Disconnect the O2S connector for the sensor that applies to this DTC.
  3. Leave the AF ECU disconnected.
  4. Turn the ignition ON while leaving the engine OFF.
  5. Using a scan tool monitor the O2S voltage for the sensor that applies to this DTC.

Is the O2S voltage WITHIN the value range specified?

351 to 551  mV

Go to Step 8

Go to Step 9

8

The O2S is detecting a rich exhaust condition or may be contaminated. Inspect for one of the following conditions:

    • O2S connector water intrusion
    • Silicon contaminated O2S
    • Fuel contaminated engine oil
    • EVAP canister purge system malfunction
    • Incorrect fuel pressure
    • A leaking gasoline fuel pressure regulator

Repair any of the above or similar engine conditions as necessary.

Was a condition found and repaired?

--

Go to Step 15

Go to Step 13

9
  1. Turn the ignition OFF.
  2. Disconnect the O2S High signal circuit from the gasoline control module (VCM/PCM or ECM) connector.
  3. Turn the ignition ON leaving the engine OFF.
  4. Using the J 39200 DMM measure the voltage between the O2S High signal circuit terminal (harness side) and ground.

Is the voltage measured GREATER than the value specified?

20 mV

Go to Step 10

Go to Step 14

10

Repair the O2S signal High circuit shorted to voltage.

Is the action complete?

--

Go to Step 15

--

11

The O2S may be detecting a rich exhaust condition only during CNG operation.

Perform the Fuel System Diagnosis and return to this step.

Was a rich AF fuel system condition found and repaired?

--

Go to Step 15

Go to Step 12

12
  1. Replace the AF ECU. Refer to Engine Control Unit Replacement .
  2. Program (flash) the replacement control module with the correct vehicle software and calibration.

Is the replacement complete?

--

Go to Step 15

--

13

Replace the O2S. Refer to Oxygen Sensor Replacement in Engine Controls-2.2L (LN2) in the J Platform Service Manual.

Is the action complete?

--

Go to Step 15

--

14

Important: The following control module replacement procedures must all be completed before attempting to operate the vehicle.

  1. Replace the gasoline control module (VCM/PCM or ECM). Refer to Powertrain Control Module Programming .
  2. Program (flash) the replacement control module with the correct vehicle software and calibration.

    3. Important: In order to perform the variation learn procedure a switch-over to gasoline operation is necessary. Remove the CNG 20 amp fuse in order to perform the switch-over.

  3. Perform the Crankshaft Position System Variation Learn in Engine Controls-2.2L (LN2) in the J Platform Service Manual.

    4. All of the above procedures are located in the gasoline service manual.

Is the replacement complete?

--

Go to Step 15

--

15
  1. Reconnect all disconnected or removed components, connectors, fuses, etc.
  2. Using a scan tool clear all DTC Information from BOTH the gasoline control module (VCM/PCM or ECM) and the AF ECU.
  3. Using the scan tool communicate with the BOTH the gasoline control module and the AF ECU in order to reset the Fuel Trim values to zero.
  4. Start the engine.
  5. Operate the vehicle within the Conditions for Running this DTC until the scan tool indicates the diagnostic ran.

Does the scan tool indicate the DTC passed?

--

System OK

Go to Step 2