GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2005 🢒 Matiz 🢒 DTC 🢒 DTC P0133

Circuit Description

The oxygen sensors (O2S) is used for fuel control and catalyst monitoring. The O2S 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 O2S signal voltage while calculating the air-to-fuel ratio. The control module supplies the O2S with a reference, or bias voltage of about 450 mV. While the engine runs, the O2S 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 O2S voltage fluctuation is observed by the control module, Closed Loop is entered. The control module uses the O2S voltage to determine the air-to-fuel ratio. An O2S voltage that increases above bias voltage toward 1,000 mV indicates a rich fuel mixture. An O2S voltage that decreases below bias voltage toward 0 mV indicates a lean fuel mixture.

The O2S utilizes the following circuits:

    • A signal circuit
    • A low reference circuit

The ECM monitors the rich-to-lean and lean-to-rich response time. A response time is defined as the HO2S voltage changes from above 600 mV to below 300 mV or from below 300 mV to above 600 mV. If the ECM detects that the response time is too long, this DTC sets.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P0133 O2S Slow Response Sensor 1

Conditions for Running the DTC
    • DTCs P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0131, P0132, P0137, P0138, P0300, P0335, P0336, P0341, P0400, P0404, P0405, P0444, and P0445 are not set.
    • The engine coolant temperature is more than 60°C (140°F).
    • The ignition 1 voltage is more than 10 volts.
    • The fuel system is in closed loop.
    • The engine speed is between 1,800-2,900 RPM.
    • The vehicle speed is between 45-55 km/h (28-34 mph).
    • The mass air flow (MAF) is between 60-160 mg/tdc.
    • The manifold air pressure (MAP) is more than 70 kPa.
    • The DTC runs continuously once the above conditions are met.

Conditions for Setting the DTC

The ECM detects that the HO2S rich-to-lean average response time or lean-to-rich average response time is more than 3 times the normal transition time for 10-20 minutes depending on engine load and speed.

Or

The ECM detects that the HO2S signal spends more time in the rich region as compared to the lean region or the HO2S signal spends more time in the lean region as compared to the rich region for 10-20 minutes depending engine load and speed.

Action Taken When the DTC Sets
    • The malfunction indicator lamp (MIL) will illuminate.
    • The coolant fan turns ON.
    • The vehicle will operate in Open Loop.

Conditions for Clearing the MIL/DTC
    • The MIL will turn OFF after 4 consecutive ignition cycles in which the diagnostic runs without a fault.
    • DTCs can be cleared by using the scan tool.
    • Disconnect the ECM battery feed for 10 seconds.

Test Description

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

  1. This step determines if the condition is present. This test may take 5-10 minutes for the diagnostic to run.

    2.

  2. An exhaust leak 6-12 inches away from the O2S can cause a DTC to set.

    3.

  3. Certain RTV silicone gasket materials release vapors that can contaminate the O2S. Silicone in the fuel can also cause silicone contamination. If the sensors appear contaminated by silicone, and if all the silicone sealant is a non-silicone base, advise the customer to try a different fuel company. A missing fuel filler restrictor indicates that the customer may have used leaded fuel.

Step

Action

Yes

No

Schematic Reference: Engine Controls Schematics

Connector End View Reference: Engine Control Module Connector End Views or Engine Controls Connector End Views

1

Did you perform the Diagnostic System Check - Engine Controls?

Go to Step 2

Go to Diagnostic System Check - Engine Controls

2

Important: If any other DTCs are set, refer to those DTCs before proceeding with this diagnostic table.

  1. Allow the engine to reach the normal operating temperature.
  2. Operate the vehicle within the parameters specified in Conditions for Running the DTC.
  3. Observe the diagnostic trouble code (DTC) information with a scan tool.

Does the DTC fail this ignition?

Go to Step 4

Go to Step 3

3
  1. Turn OFF the ignition for 30 seconds.
  2. Start the engine.
  3. Operate the vehicle within the Conditions for Running the DTC.

Did the DTC fail this ignition?

Go to Step 4

Go to Intermittent Conditions

4

Inspect for an exhaust leak near the O2S. After you inspect the exhaust system, return to this diagnostic.

Did you find and correct the condition?

Go to Step 7

Go to Step 5

5

Inspect or test for the following conditions:

    • The O2S is securely installed.
    • Inspect for corrosion on the O2S terminals.
    • Inspect the terminal tension at the O2S and at the ECM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.
    • Inspect the O2S wiring for damage. Refer to Wiring Repairs in Wiring Systems.
    • Fuel that is contaminated.
    • Inspect for the correct RTV sealant.
    • Inspect for engine oil consumption.
    • Inspect for engine coolant consumption. Refer to Loss of Coolant in Engine Cooling.

Did you find and correct the condition?

Go to Step 7

Go to Step 6

6

Replace the O2S. Refer to Oxygen Sensor Replacement .

Did you complete the replacement?

Go to Step 7

--

7
  1. Clear the DTCs with a scan tool.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC.

Did the DTC fail this ignition?

Go to Step 2

Go to Step 8

8

Are there any DTCs that have not been diagnosed?

Go to Diagnostic Trouble Code (DTC) List

System OK