GM Service Manual Online
For 1990-2009 cars only

Circuit Description

When the vehicle is first started, the engine operates in an open loop operation, ignoring the oxygen sensor signal and calculating the air-to-fuel ratio based on inputs from the engine coolant temperature (ECT), the throttle position (TP), and the manifold absolute pressure (MAP) sensors only. The powertrain control module (PCM) will begin by using the oxygen sensor (O2S) signal in order to control the fuel delivery in a closed loop when the following conditions are met:

    • The engine has run a minimum amount of time based on ECT at engine start-up.
    • The oxygen sensor (O2S) 1 has a varying voltage output. This voltage output indicates that the O2S is hot enough to operate properly.
    • The ECT has increased a minimum amount based on the ECT at engine start-up.

Conditions For Running The DTC

    • DTCs P0105, P0107, P0108, P0117, P0118, P0122, P0123, P0125, P0128, P0131, P0132, P0133, P0134, P0171, P0172, P0201-P0204, P0300, P0301-P0304, P0325, P0336, P0440, P0442, P0446, P0452, P0453, P0502, P0601, P0602, P1133, P1441, or P1621 are not set.
    • The engine has been running more than 100 seconds.
    • The engine speed is between 1,200-3,400 RPM.
    • The throttle position (TP) angle is between 10-40 percent.
    • The engine coolant temperature ECT is more than 60°C (140°F).
    • The above conditions have been met for 2 seconds.

Conditions For Setting The DTC

The engine is not in closed loop for 5 seconds out of 12.5 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.

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

DTC P0130 or a slow response is most likely caused by one of the following items:

O2S 1 contamination--Inspect the O2S 1 for silicone contamination from fuel or the use of improper room-temperature vulcanizing (RTV) sealant. The O2S 1 sensor may have a white powdery coating, which will result in a high but false voltage signal indicative of rich exhaust . The PCM will then reduce the amount of fuel delivered to the engine, and cause a severe surge or driveability problem.

Test Description

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

  1. When the system is operating correctly, the HO2S voltage should toggle above and below the specified values.

  2. The specified value is what is measured on a correctly operating system.

  3. The specified value is what is measured on a correctly operating system.

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

Important: If any other DTCs are set except for HO2S DTCs, refer to the other DTCs first before proceeding with this table.

  1. Be sure the engine is at the normal operating temperature.
  2. Operate the engine at more than 1200 RPM for 2 minutes.
  3. With a scan tool, observe the O2 voltage parameter.

Does the scan tool indicate that the O2 voltage is more than or less than the specified values?

400-500 mV

Go to Step 3

Go to Step 4

3

Operate the vehicle within the Failure Records conditions.

Does the scan tool indicate that this DTC failed this ignition?

--

Go to Step 4

Go to Diagnostic Aids

4

Inspect and test for the following:

    • An exhaust leak. Refer to Exhaust Leakage in Engine Exhaust.
    • The O2 is installed correctly.
    • Damaged wiring. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 13

Go to Step 5

5

  1. Turn OFF the ignition.
  2. Disconnect the O2S sensor.
  3. Jumper the O2S low signal circuit to a good ground.
  4. Turn ON the ignition, with the engine OFF.
  5. Measure the voltage on the O2S high signal circuit on the PCM side, using a DMM that is connected to a good ground.

Does the voltage measure within the specified value?

351-551 mV

Go to Step 6

Go to Step 8

6

  1. Jumper the high signal circuit to the low signal circuit on the PCM side.
  2. With a scan tool, observe the O2 voltage parameter.

Does the scan tool indicate O2 voltage at or near the specified value?

0 mV

Go to Step 9

Go to Step 7

7

Test the low signal circuit for an open, high resistance, or short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 13

Go to Step 11

8

Test the high signal circuit for an open, high resistance, or short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 13

Go to Step 11

9

Test for faulty connections at the O2 sensor. 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 13

Go to Step 10

10

Important: Determine the cause of contamination before replacing the sensor.

Inspect and test for the following:

    • Fuel Contamination--Refer to Alcohol/Contaminants-in-Fuel Diagnosis .
        Engine oil or coolant consumption--Refer to Oil Consumption Diagnosis in Engine Mechanical.
    • Use of an improper RTV sealant

Replace the affected O2 sensor. Refer to Oxygen Sensor Replacement .

Did you complete the replacement?

--

Go to Step 13

--

11

Test for faulty connections at 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 13

Go to Step 12

12

Replace the PCM. Refer to Powertrain Control Module Replacement .

Did you complete the replacement?

--

Go to Step 13

--

13

  1. Use a 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 14

Go to Step 2

14

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