GM Service Manual Online
For 1990-2009 cars only
Table 1: HO2S Voltages

Circuit Description

This diagnostic detects a loose or un-installed sensor. When the heated oxygen (HO2S) sensor is not securely connected to the exhaust pipe, the HO2S feedback indicates normal atmosphere conditions. When the HO2S output stays out of normal range after the HO2S is active, the powertrain control (PCM) module detects the HO2S is disconnected from the exhaust pipe, and this DTC will set.

DTC Descriptors

This diagnostic procedure supports the following DTC.

DTC P2414 HO2S Exhaust Sample Bank 1 Sensor 1

Conditions for Running the DTC

    • DTCs P0030, P0135, P2238, P2239, P2243, P2245, P2252, P2253, P2627, P2628 are not set.
    • The engine is running.
    • Engine coolant temperature (ECT) at least -20°C (-4°F).
    • A fuel cut-off condition has not occurred in more than 5 seconds.
    • DTC P2414 runs once per drive cycle when the above conditions are met.

Conditions for Setting the DTC

The HO2S output voltage is more than 2.2 volts.

The above condition is met for at least 7  seconds.

Action Taken When the DTC Sets

    • The PCM illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
    • The PCM records the operating conditions at the time the diagnostic fails. The PCM stores this information in the Freeze Frame and/or Failure Records.

Conditions for Clearing the MIL/DTC

    • The PCM turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
    • A last test failed, or current DTC, clears when the diagnostic runs and does not fail.
    • A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
    • Use a scan tool in order to clear the MIL and the DTC.

Diagnostic Aids

    • Use the J-35616 Connector Test Adapter Kit for any test that requires probing the PCM harness connector or a component harness connector.
    • The Loop Status for the respective bank will default to Open when the DTC is current.
    • The wide band sensors do not toggle or switch like a switching HO2S. The HO2S signals will be relatively stable for an idling engine.
    • For an intermittent condition, refer to Intermittent Conditions .
    • The following table illustrates the typical voltages for the HO2S circuits:

HO2S Voltages

    • Ignition On, Engine Off
    • HO2S Disconnected

HO2S Circuit

Voltage

Heater Control

Less than 0.5 V

Heater Supply Voltage

B+

Reference Voltage

3.3-3.8 V

Low Reference

5.9-6.4 V

Pump Current

4.8-5.3 V

Input Pump Current

3.3-3.8 V

Test Description

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

  1. This step verifies that there is no other condition with the HO2S circuits.

  2. This step verifies that a condition exists. If the HO2S is secure in the exhaust system and the DTC fails this ignition, replace the HO2S.

Step

Action

Yes

No

1

Did you perform the Diagnostic System Check-Engine Controls?

Go to Step 2

Go to Diagnostic System Check - Engine Controls

2

  1. Turn ON the ignition, with the engine OFF.
  2. Observe the DTC information with a scan tool.

Is DTC P2238, P2239, P2243, P2245, P2252, P2253, P2627, or P2628 set?

Go to Diagnostic Trouble Code (DTC) List

Go to Step 3

3

Inspect the condition of the appropriate HO2S.

Is the HO2S loose in the exhaust pipe?

Go to Step 5

Go to Step 4

4

  1. Observe the Freeze Frame/Failure records data for this DTC.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure records data.

Did the DTC fail this ignition cycle?

Go to Step 6

Go to Diagnostic Aids

5

Reinstall the appropriate HO2S.

Did you complete the repair?

Go to Step 7

--

6

Replace the HO2S sensor. Refer to Heated Oxygen Sensor Replacement - Bank 1 Sensor 1 .

Did you complete the replacement?

Go to Step 7

--

7

  1. Use the scan tool in order to clear the DTCs.
  2. Turn OFF the ignition for 90 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC.

Does the DTC run and pass?

Go to Step 8

Go to Step 2

8

With a scan tool, select Capture Info in order to observe the stored information.

Does the scan tool display any DTCs that you have not diagnosed?

Go to Diagnostic Trouble Code (DTC) List

System OK