GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Saturn 🢒 2007 🢒 VUE - AWD 🢒 Engine 🢒 Engine Controls and Fuel - 3.5L (L66) 🢒 DTC P0135 or P0155
Table 1: HO2S Voltages

Circuit Description

Heating elements inside the heated oxygen sensor (HO2S) minimize the time required for the sensors to reach operating temperature and to provide an accurate voltage signal. A low side driver within the powertrain control module (PCM) is pulse width controlled to provide current to the heater elements. During warm-up, the PCM will pulse the heaters ON-OFF to prevent thermal shock to the sensor components from moisture in the exhaust system. The PCM will not allow continuous HO2S heating until calibrated limits of time, temperature, and intake airflow have been reached. The PCM continuously monitors the HO2S heater current draw and operating state by briefly turning OFF the heater low side driver at regular intervals. The PCM calculates the HO2S heater element resistance based on the actual heater current. If the PCM detects that the HO2S heater element resistance is too high, this DTC will set.

Each HO2S heater has the following circuits:

    • HO2S heater ignition 1 voltage
    • HO2S heater low control

DTC Descriptors

This diagnostic procedure supports the following DTCs:

    • DTC P0135 HO2S Heater Performance Bank 1 Sensor 1
    • DTC P0155 HO2S Heater Performance Bank 2 Sensor 1

Conditions for Running the DTC
    • DTCs P0030, P0036, P0050, P0056, P0117, P0118, P2238, P2239, P2241, P2242, P2243, P2245, P2247, P2249, P2252, P2253, P2255, P2256, P2414, P2415, P2627, P2628, P2630, P2631 are not set.
    • The engine is operating for more than 90 seconds.
    • The ignition 1 voltage is between 10.5-16 volts.
    • The engine coolant temperature (ECT) is more than -20°C (-4°F).
    • The system is not in fuel cut-off mode for at least 40 seconds.
    • DTCs P0135 and P0155 run continuously once the above conditions are met.

Conditions for Setting the DTC
    • The calculated internal resistance of the HO2S is more than 110 ohms for more than 40 seconds after an engine start.
        OR
    • The calculated internal resistance of the HO2S is more than 110 ohms for more than 15 seconds.
    • The calculated internal resistance of the HO2S is more than 200 ohms for more than 1 second.
    • The air/fuel ratio (A/F) sensor heater internal output voltage is 0.76 volt or more.
    • The A/F sensor heater internal output voltage is 0.24 volt or less.

Action Taken When the DTC Sets
    • The PCM illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
    • The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the PCM stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the PCM records the operating conditions at the time of the failure. The PCM writes the conditions to the Freeze Frame and updates the 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

HO2S Circuit

Voltage

    • Ignition On, Engine Off
    • HO2S Disconnected

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 tests for high resistance in the ignition 1 voltage circuit of the HO2S. If the DMM does not display near battery voltage, repair the high resistance in the ignition 1 voltage circuit.

    2.

  2. This step tests the HO2S heater control circuit for a high resistance. Six amps through the DMM is normal when the HO2S heater control circuit is commanded ON with a scan tool. A high resistance in the circuit will cause the amperage to be less than 1 amp. Test the HO2S heater control circuit for a high resistance if the DMM displays a reading of less than 1 amp.

    3.

  3. This step tests the HO2S input pump current circuit for a wire to wire short to the reference voltage circuit or a condition internal to the PCM. If the resistance measured between the circuits is more than 110,000 ohms, the PCM and the circuits are OK.

    4.

  4. This step isolates the condition. Test for a wire to wire short between the HO2S input pump current and reference voltage circuits, if any continuity exists between the circuits.

    5.

  5. Inspect the HO2S connector for water intrusion, corrosion, and bent or damaged terminals.

    6.

  6. Inspect the PCM connectors for water intrusion, corrosion, and bent or damaged terminals.

Step

Action

Values

Yes

No

Schematic Reference: Engine Controls Schematics

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

1

Did you perform the Diagnostic System Check - Vehicle?

--

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

Important: DTC P0135 is for bank 1 sensor 1 - rear and DTC P0155 is for bank 2 sensor 1 - front.

  1. Start the engine.
  2. Allow the engine to reach operating temperature.
  3. Observe the DTC info with a scan tool for at least 40 seconds.

Does the DTC fail this ignition?

--

Go to Step 4

Go to Step 3

3
  1. Observe the Freeze Frame/Failure Records 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 as specified in the supporting text or as close to the Freeze Frame/Failure Records that you observed.

Does the DTC fail this ignition?

--

Go to Step 4

Go to Diagnostic Aids

4

  1. Turn OFF the ignition.
  2. Disconnect the affected heated oxygen sensor (HO2S) 1 connector.
  3. Turn ON the ignition.
  4. Connect a test lamp between the ignition 1 voltage circuit of the HO2S and a good ground.
  5. Connect a DMM to the probe of the test lamp and a good ground. Refer to Measuring Voltage Drop .

Does the voltage measure at the specified value?

B+

Go to Step 5

Go to Step 17

5

  1. Set up a DMM to test amperage on the 10 amp scale.
  2. Connect the DMM between the ignition 1 circuit and the heater control circuit of the HO2S.
  3. Observe the amperage on the DMM while the HO2S heater is being commanded ON with a scan tool.

Is the amperage more than the specified value?

1 A

Go to Step 6

Go to Step 11

6

Measure the voltage between the HO2S reference voltage circuit and a good ground with a DMM.

Is the voltage within the specified range?

3.3-3.8 V

Go to Step 7

Go to Step 12

7

Measure the voltage between the HO2S low reference circuit and a good ground with a DMM.

Is the voltage within the specified range?

5.9-6.4 V

Go to Step 8

Go to Step 13

8

Measure the voltage between the HO2S input pump current circuit and a good ground with a DMM.

Is the voltage within the specified range?

3.3-3.8 V

Go to Step 9

Go to Step 14

9

  1. Turn the ignition OFF for 1 minute.
  2. Measure the resistance between the HO2S input pump current circuit and the HO2S reference voltage circuit.

Is the resistance less than the specified value?

110 Kohms

Go to Step 10

Go to Step 15

10

  1. Disconnect the appropriate powertrain control module (PCM) connector.
  2. Measure the resistance between the HO2S input pump current circuit and the HO2S reference voltage circuit.

Is the resistance at the specified value?

OL

Go to Step 16

Go to Step 18

11

Test the HO2S heater control circuit for a high resistance. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 21

Go to Step 16

12

Test the HO2S reference voltage circuit for an open, a high resistance, or a short to ground. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 21

Go to Step 16

13

Test the HO2S low reference circuit for one of the following conditions:

    • An open
    • A high resistance
    • A short to voltage
    • A short to the HO2S pump current circuit
    • A short to the HO2S reference voltage circuit--Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 21

Go to Step 16

14

Test the HO2S input pump current circuit for an open, a high resistance, or a short to voltage. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 21

Go to Step 16

15

Test for shorted terminals and for poor connections at the HO2S. Refer to Testing for Intermittent Conditions and Poor Connections and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 21

Go to Step 19

16

Test for shorted terminals and for poor connections at the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 21

Go to Step 20

17

Repair the open or high resistance in the HO2S heater ignition 1 circuit. Refer to Wiring Repairs .

Did you complete the repair?

--

Go to Step 21

--

18

Repair the short between the HO2S input pump current circuit and the HO2S reference voltage circuit.

Did you complete the repair?

--

Go to Step 21

--

19

Replace the HO2S. Refer to the appropriate procedure:

Did you complete the replacement?

--

Go to Step 21

--

20
  1. Replace the PCM. Refer to Control Module References for replacement, setup, and programming.
  2. Perform the idle learn procedure. Refer to Idle Learn .

Did you complete the replacement?

--

Go to Step 21

--

21
  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. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.

Did the DTC fail this ignition?

--

Go to Step 2

Go to Step 22

22

Observe the Capture Info with a scan tool.

Are there any DTCs that have not been diagnosed?

--

Go to Diagnostic Trouble Code (DTC) List - Vehicle

System OK