GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2005 🢒 Matiz 🢒 Engine 🢒 Engine Controls - 1.0L 🢒 DTC P0141

Circuit Description

The heated oxygen sensors (HO2S) are used for fuel control and post catalyst monitoring. Each HO2S compares the oxygen content of the surrounding air with the oxygen content in the exhaust stream. The HO2S must reach operating temperature to provide an accurate voltage signal. A heating element inside the HO2S minimizes the time required for the sensor to reach operating temperature. Voltage is provided to the heater by the ignition 1 voltage circuit through a fuse. Ground is provided to the heater on the low control circuit by a low side driver within the control module. The control module monitors the current draw of the heater to determine if a failure is present.

If the ECM detects that the HO2S 2 heater current is below a specified value, this DTC sets.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P0141 HO2S Heater Performance Sensor 2

Conditions for Running the DTC
    • The engine run time is more than 1 minute.
    • The ignition 1 voltage is more than 10 volts.
    • DTC P0141 runs continuously once the above conditions are met.

Conditions for Setting the DTC

The ECM detects that the HO2S 2 heater current is less than 10 ohms or greater than 30 ohms.

Action Taken When the DTC Sets
    • The malfunction indicator lamp (MIL) will illuminate after 3 consecutive trips with a fail.
    • The ECM will record operating conditions at the time the diagnostic fail. This information will be stored in the Freeze Frame and Failure Records buffers.
    • The coolant fan turns ON.

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 number below refers to the step number on the diagnostic table.

  1. This step is testing the heater control circuit for a short to ground.

    2.

  2. This step is testing the heater control circuit for an open or for a short to voltage.

    3.

  3. This step is testing the heater control circuit for high resistance. If the voltage is more than the specified value, test the circuit for high resistance.

Step

Action

Values

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
  1. Start the engine.
  2. Allow the engine to reach the normal operating temperature.
  3. Operate the engine above 1,200 RPM for 30 seconds and then allow the engine to idle.

    4. Important: It may take up to 8 minutes for this DTC to set.

  4. Observe the DTC Information with a scan tool.

Did DTC P0141 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
  1. Disconnect the HO2S 2.
  2. Turn ON the ignition, with the engine OFF.
  3. Probe the ignition 1 voltage circuit of the HO2S 2 with a test lamp that is connected to a good ground.

Does the test lamp illuminate?

--

Go to Step 5

Go to Step 13

5
  1. Turn OFF the ignition.
  2. Disconnect the fuse that supplies ignition 1 voltage to the HO2S 2 heater.
  3. Measure the resistance of the ignition 1 voltage circuit of the HO2S 2 heater from the fuse terminal to the harness connector terminal of the HO2S 2 heater.

Is the resistance less than the specified value?

3 ohms

Go to Step 6

Go to Step 13

6

  1. Turn OFF the ignition.
  2. Connect a test lamp between the control circuit of the HO2S 2 heater and battery positive voltage.

Does the test lamp illuminate?

--

Go to Step 9

Go to Step 7

7

  1. Start the engine.
  2. Connect a test lamp between the control circuit of the HO2S 2 heater and battery positive voltage.

Does the test lamp illuminate?

--

Go to Step 8

Go to Step 9

8

    Important: Use a test lamp that measures between 25-30 ohms.

  1. Probe the control circuit of the HO2S 2 heater with a test lamp connected to battery positive voltage.

    2. Important: Allow the voltage to stabilize on the DMM. Voltage will fluctuate, which is normal.

  2. Measure the voltage from the probe of the test lamp to a good ground.

Is the voltage less than the specified value?

0.3 V

Go to Step 11

Go to Step 10

9

Test the control circuit of the HO2S 2 heater for one of the following conditions:

    • A short to voltage
    • An open
    • A short to ground

Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 16

Go to Step 12

10

Test the control circuit of the HO2S 2 heater for high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 16

Go to Step 12

11

Test for an intermittent and poor connection at the HO2S 2. 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 16

Go to Step 14

12

Test for an intermittent and poor connection at the ECM. 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 16

Go to Step 15

13
  1. Repair the ignition 1 voltage circuit of the HO2S 2 heater for one of the following conditions:
    2. • An open
    • A short to ground
    • High resistance
  2. Replace the fuse as necessary.

Did you complete the repair?

--

Go to Step 16

--

14

Replace the HO2S 2. Refer to Heated Oxygen Sensor 2 Replacement .

Did you complete the replacement?

--

Go to Step 16

--

15

Replace the ECM. Refer to Engine Control Module Replacement .

Did you complete the replacement?

--

Go to Step 16

--

16
  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 17

17

Are there any DTCs that have not been diagnosed?

--

Go to Diagnostic Trouble Code (DTC) List

System OK