GM Service Manual Online
For 1990-2009 cars only

Diagnostic Instructions

    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provide an overview of each diagnostic category.

DTC Descriptors

DTC P0130: HO2S Circuit Closed Loop (CL) Performance Bank 1 Sensor 1

DTC P0150: HO2S Circuit Closed Loop (CL) Performance Bank 2 Sensor 1

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

HO2S Bank 1 Sensor 1 Signal

P0131

P0130

P0132

P0130, P0133, P0134

HO2S Bank 1 Sensor 2 Signal

P0137

P0136

P0138

P0136, P0139, P0140

HO2S Bank 2 Sensor 1 Signal

P0151

P0150

P0152

P0150, P0153, P0154

HO2S Bank 2 Sensor 2 Signal

P0157

P0156

P0158

P0156, P0159, P0160

Low Reference

--

P0130, P0136, P0150, P0156

P0132, P0138, P0152, P0158

--

Typical Scan Tool Data

HO2S 1 or 2

Circuit

Short to Ground

Open

Short to Voltage

Operating Conditions: Engine operating in Closed Loop.

Parameter Normal Range: Fluctuates above and below 350-500 mV.

Sensor Signal

0-60 mV

400-415 mV

5000 mV

Low Reference

--

400-415 mV

5000 mV

Circuit Description

The heated oxygen sensors (HO2S) are used for fuel control and catalyst monitoring. Each HO2S compares the oxygen content of the surrounding air with the oxygen content of the exhaust stream. When the engine is started, the control module operates in an Open Loop mode, ignoring the HO2S signal voltage while calculating the air-to-fuel ratio. The control module supplies the HO2S with a reference, or bias voltage of about 450 mV. While the engine runs, the HO2S heats up and begins to generate a voltage within a range of 0-1,000 mV. This voltage will fluctuate above and below the bias voltage. Once sufficient HO2S voltage fluctuation is observed by the control module, Closed Loop is entered. The control module uses the HO2S voltage to determine the air-to-fuel ratio. An HO2S voltage that increases above bias voltage toward 1,000 mV indicates a rich fuel mixture. An HO2S voltage that decreases below bias voltage toward 0 mV indicates a lean fuel mixture.

The heating elements inside each HO2S heat the sensor to bring the sensor up to operating conditions faster. This allows the system to enter Closed Loop earlier and the control module to calculate the air-to-fuel ratio sooner.

The HO2S utilizes the following circuits:

    • A signal circuit
    • A low reference circuit
    • An ignition 1 voltage circuit
    • A heater control circuit

Conditions for Running the DTCs

    • DTCs P0131, P0132, P0133, P0134, P0151, P0152, P0153, P0154, P0562, and P0563 are not set.
    • The engine is running.
    • The HO2S heaters are ON.
    • The ignition 1 voltage is more than 10 volts.
    • The HO2S voltage is between 376-474 mV.
    • The exhaust gas temperature at the HO2S is greater than 350°C (662°F).
    • The DTCs run continuously once the above conditions are met.

OR

    • DTCs P0131, P0132, P0133, P0134, P0151, P0152, P0153, and P0154 are not set.
    • The ignition is ON.
    • The exhaust gas temperature at the HO2S is less than 600°C (1,112°F).
    • The DTCs run continuously once the above conditions are met.

Conditions for Setting the DTCs

The engine control module (ECM) detects the HO2S resistance is greater than 60K Ohms for 10 seconds.

Action Taken when the DTCs Set

DTCs P0130 and P0150 are Type B DTCs.

Conditions for Clearing the MIL/DTC

DTCs P0130 and P0150 are Type B DTCs.

Reference Information

Schematic Reference

Engine Controls Schematics

Connector End View Reference

    •  Engine Control Module Connector End Views
    •  Engine Controls Connector End Views

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

    •  Scan Tool Data List
    •  Scan Tool Data Definitions
    •  Scan Tool Output Controls

Circuit/System Verification

  1. Engine idling, observe the scan tool HO2S voltage parameter. The reading should fluctuate above and below the range of 350-550 mV.
  2. If the vehicle passes the Circuit/System Verification test, then operate the vehicle within the conditions for running the DTC. You may also operate the vehicle within the conditions that are captured in the Freeze Frame/Failure Records Data List.

Circuit/System Testing

  1. Ignition OFF, disconnect the harness connector at the appropriate HO2S sensor.
  2. Ignition ON, test for less than 0.1 volt between the low reference circuit and ground.
  3. If greater than the specified range, test the low reference circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM.
  4. Verify the scan tool HO2S parameter is between 350-500 mV.
  5. If less than the specified range, test the signal circuit for a short to ground. If the circuit tests normal, replace the ECM.
    If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the ECM.
  6. Install a 3-A fused jumper wire between the signal circuit and the low reference circuit. Verify the scan tool HO2S sensor parameter is less than 60 mV.
  7. If greater than the specified range, test the signal circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
  8. If all circuits test normal, replace the HO2S sensor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for engine control module replacement, setup, and programming