GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Oldsmobile 🢒 2001 🢒 Aurora 🢒 DTC 🢒 DTC P1134

Circuit Description

The powertrain control module (PCM) continuously monitors the heated oxygen sensor (HO2S) activity for 100 seconds. During the monitor period the PCM counts the number of times that the HO2S transitions from rich to lean and from lean to rich and adds the amount of time it took to complete all transitions. With this information, an average time for all transitions can be determined. The PCM then divides the rich to lean average by the lean to rich average to obtain a ratio. If the HO2S transition time ratio is not within range, DTC P1134 will set, indicating that the oxygen sensor is not responding as expected to changes in exhaust oxygen content.

Conditions for Running the DTC
    • DTCs P0101, P0102, P0103, P0106, P0107, P0108, P0111, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0131, P0132, P0135, P0200, P0300, P0410, P0412, P0418, P0440, P0442, P0443, P0446, P0449, P1106, P1107, P1111, P1112, P1114, P1115, P1121, P1122, P1133, or P1441 are not set.
    • The system voltage is more than 9 volts.
    • The engine is running in Closed Loop.
    • The engine is running for at least 4 minutes.
    • The engine coolant temperature (ECT) is more than 75°C (167°F).
    • The transmission is in drive.
    • The engine speed is between 1,200-2,500 RPM.
    • The mass air flow (MAF) is between 15-35 gm/s.
    • The above conditions are stable for 3 seconds.

Conditions for Setting the DTC

The PCM detects degraded, or slow, rich to lean or lean to rich response times for HO2S 1.

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

Notice: Use the connector test adapter kit J 35616-A for any test that requires probing the following items:

   • The PCM harness connectors
   • The electrical center fuse/relay cavities
   • The component terminals
   • The component harness connector
Using this kit will prevent damage caused by the improper probing of connector terminals.

A malfunction in the HO2S heater ignition feed or ground circuit may cause the DTC to set. Check HO2S heater circuitry for intermittent malfunctions or poor connections. If connections and wiring are OK and the DTC continues to set, the HO2S may be at fault.

Reviewing the Failure Records vehicle mileage since the diagnostic test last failed may help determine how often the condition occurs that caused the DTC to set. This may assist in diagnosing the condition.

If the problem is intermittent, refer to Intermittent Conditions .

Test Description

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

  1. HO2S contamination may cause multiple HO2S diagnostic trouble codes (DTCs) to set.

    2.

  2. The use of leaded fuel may be indicated by the removal or tampering of the fuel filler restrictor.

    An HO2S contaminated by silicon will have a white, powdery deposit on the portion of the HO2S that is exposed to the exhaust stream. The usual cause of silica contamination is the use of unapproved silicon RTV engine gasket material, the use of silicon based sprays or fluids within the engine or coolant consumption. Phosphorus contamination also leaves a white powdery coating on the HO2S. Phosphorus contamination comes from oil consumption. If the cause of this contamination is not corrected, the replacement HO2S will also get contaminated.

    3.

  3. Even small exhaust leaks can cause slow response from the HO2S.

    4.

  4. An HO2S contaminated by silicon will have a white, powdery deposit on the portion of the HO2S that is exposed to the exhaust stream. The usual cause of silica contamination is the use of un-approved silicon RTV engine gasket material, the use of silicon based sprays or fluids within the engine or coolant consumption. Phosphorus contamination also leaves a white powdery coating on the HO2S. Phosphorus contamination comes from oil consumption. If the cause of this contamination is not corrected, the replacement HO2S will also get contaminated.

    5.

  5. If the voltage observed in step 8 is less than the range specified, a short between the high and low circuits or a short between the high circuit and ground is indicated. With the HO2S and the PCM disconnected, the resistance between the high and low circuits and the resistance between the high circuit and ground should measure infinite.

    If the voltage observed in step 8 is more than the range specified, a short between the high circuit and an ignition voltage source is indicated.

    6.

  6. If the voltage observed in step 9 is not below the voltage specified, a high resistance (open) high or low circuit is indicated.

    Good circuit continuity measures less than 5 ohms with the PCM and sensor disconnected. Measure between the PCM connector and the HO2S connector. Ensure PCM terminal contact is good.

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

Is DTC P0140 also set?

--

Go to Step 4

Go to Step 3

3

Are any powertrain component DTCs set?

--

Go to the applicable DTCs

Go to Step 5

4

  1. The HO2S has been contaminated. Replace the affected HO2S. Refer to Heated Oxygen Sensor 1 Replacement .
  2. The contamination source MUST be removed prior to operating the engine with the replacement sensors. Possible sources include the following:
    3. • The use of incorrect silicon RTV sealant
    • Engine coolant leakage into the combustion chamber
    • Excessive engine oil consumption
    • The use of silicon contaminated fuel
    • The use of fuel containing LEAD

Has the contamination source been removed and the affected sensors replaced?

--

Go to Step 18

--

5
  1. Use a scan tool in order to store DTC information from the PCM into the scan tool.
  2. Clear the DTC information from the PCM.
  3. Reset the fuel trim values.
  4. Start and idle the engine until normal operating temperature is reached.
  5. Operate the engine under the Conditions for Running the DTC.
  6. Observe the DTC status and verify that this DTC Runs.

Did this DTC run and fail this ignition?

--

Go to Step 7

Go to Step 6

6

The condition that set this DTC is not present. This DTC may have been set by one of the following conditions:

    • An exhaust system leak between the engine and the HO2S
    • Poor HO2S connector terminal contact
    • HO2S connector water intrusion
    • An improperly torqued HO2S
    • An HO2S with an inoperative heater
    • Poor PCM connector terminal contact
    • HO2S high or low circuits with one of the following conditions:
       - Intermittently open
       - Intermittently shorted
       - Excessive circuit resistance, above 5 ohms
    • A contaminated HO2S
        Contamination can include the following:
       - Contaminated fuel
       - Use of incorrect RTV sealant
       - Excessive engine oil or coolant consumption

Repair any of the above or similar engine conditions as necessary.

Was a condition found and repaired?

--

Go to Step 18

Go to Diagnostic Aids

7

  1. Check the exhaust system for leaks between the HO2S and the engine.
  2. Repair the exhaust as necessary.
  3. Check the HO2S and PCM connectors for correct terminal contact.
  4. Repair the terminal contact as necessary. Refer to Connector Repairs or Wiring Repairs in Wiring Repairs.

Was a repair made?

--

Go to Step 18

Go to Step 8

8
  1. Turn the ignition OFF.
  2. Disconnect the HO2S connector for the sensor that applies to this DTC.
  3. Jumper the engine harness side of the HO2S low reference circuit terminal to a known good ground.
  4. Turn ON the ignition, with the engine OFF.
  5. Use a scan tool in order to monitor the HO2S voltage for the sensor that applies to this DTC.

Is the HO2S voltage within the value range specified?

351-551 mV

Go to Step 9

Go to Step 13

9
  1. Jumper the HO2S high signal circuit to ground.
  2. Use a scan tool in order to monitor the HO2S voltage for the sensor that applies to this DTC.

Is the HO2S voltage less than the value specified?

20 mV

Go to Step 10

Go to Step 14

10
  1. Remove the HO2S low reference circuit jumper.
  2. Connect a test lamp between the engine harness side of the HO2S ignition 1 voltage circuit terminal and a known good ground. Do not use the HO2S heater low control circuit terminal.

Does the test lamp illuminate?

--

Go to Step 11

Go to Step 15

11

Connect the test lamp between the engine harness side of the HO2S ignition 1 voltage circuit terminal and the engine harness side of the HO2S heater low control circuit terminal.

Does the test lamp illuminate?

--

Go to Step 12

Go to Step 16

12

  1. Check for contamination sources that may have caused the HO2S to fail.

    2. HO2S contamination sources include the following:

    • Use of incorrect RTV silicon engine sealant
    • Contaminated fuel
    • Excessive engine oil or coolant consumption
  2. Repair or remove the source of the contamination.

Is the action complete?

--

Go to Step 17

--

13

  1. Check the HO2S high signal circuit for a condition. Conditions include the following:
    2. • A short between the HO2S high and low circuits or between the HO2S high signal circuit and ground
    • A short between the HO2S high signal circuit and an ignition voltage source
  2. Repair the HO2S high signal circuit as necessary. Refer to Wiring Repairs in Wiring Systems.

Is the action complete?

--

Go to Step 18

--

14

  1. Check the HO2S high signal circuit OR the HO2S low reference circuits for an open or high circuit resistance.
  2. Repair the HO2S circuits as necessary. Refer to Wiring Repairs in Wiring Systems.

Is the action complete?

--

Go to Step 18

--

15

Repair the HO2S ignition 1 voltage circuit. Refer to Wiring Repairs in Wiring Systems.

Is the action complete?

--

Go to Step 18

--

16

Repair the HO2S heater low control circuit. Refer to Wiring Repairs in Wiring Systems.

Is the action complete?

--

Go to Step 18

--

17

Replace the HO2S. Refer to Heated Oxygen Sensor 1 Replacement .

Is the action complete?

--

Go to Step 18

--

18
  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 19

Go to Step 2

19

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