GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2001 🢒 Firebird 🢒 Engine 🢒 Engine Controls - 5.7L 🢒 DTC P1134 or P1154

Circuit Description

The powertrain control module (PCM) monitors the heated oxygen sensor (HO2S) activity. During the monitoring period, the PCM counts the number of times that the HO2S responds from rich to lean and from lean to rich, and adds the amount of time needed 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 in order to obtain a ratio. A DTC P1134 or a P1154 sets if the HO2S ratio is not within range. This diagnostic runs once per ignition cycle.

Conditions for Running the DTC
    • DTCs P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0117, P0118, P121, P0122, P0123, P0200, P0300, P0410, P0440, P0442, P0446, P0452, P0453, P1258, P1415, P1416, or P1441 are not set.
    • The loop status is Closed.
    • The engine run time is more than 160 seconds.
    • The engine speed is between 1,000-2,300 RPM.
    • The ignition 1 signal is between 9-18 volts.
    • The engine coolant temperature (ECT) is more than 50°C (122°F).
    • The evaporative emissions (EVAP) purge solenoid is more than 0 percent.
    • The mass air flow (MAF) is between 20-50 g/s.
    • The throttle position (TP) is more than 5 percent.
    • The fuel tank level remaining is more than 10 percent.

Conditions for Setting the DTC

The PCM determines that the HO2S transition time ratio is more than or less than the calibrated range.

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.

Test Description

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

  1. This step determines if the condition is present. This test may take 5 minutes for the diagnostic to run.

    2.

  2. When DTCs P1134 and P1154 are set at the same time, a fuel contamination condition is likely.

    3.

  3. An exhaust leak 6-12 inches away from the HO2S can cause a DTC to set.

  4. This step tests whether a good ground circuit is available.

    5.

  5. This step tests the integrity of the HO2S high signal circuit to the PCM.

    6.

  6. This step tests the integrity of the HO2S high signal circuit to the PCM.

    7.

  7. Certain RTV silicone gasket materials release vapors that can contaminate the HO2S. Silicone in the fuel can also cause silicone contamination. If the sensors appear silicon-contaminated, and if all the silicone sealant is a non-silicone base, advise the customer to try a different fuel company. A missing fuel filler restrictor indicates the customer may have used leaded fuel.

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 DTCs are set except DTC P1134 or  P1154, refer to those DTCs before proceeding with this diagnostic table.

  1. Install a scan tool.
  2. Idle the engine at the normal operating temperature.
  3. Operate the vehicle within the parameters specified under Conditions for Running the DTC in the supporting text.
  4. Use the scan tool in order to monitor the Diagnostic Trouble Code (DTC) information.

Did DTC P1134 or P1154 fail this ignition?

--

Go to Step 3

Go to Intermittent Conditions

3

Did both DTC P1134 and P1154 fail this ignition?

--

Go to Step 8

Go to Step 4

4

  1. Inspect for an exhaust system leak. Refer to Exhaust Leakage in Engine Exhaust.
  2. If you find an exhaust leak, repair the exhaust leak as necessary.

Did you find and correct the condition?

--

Go to Step 14

Go to Step 5

5

Inspect for the following conditions:

    • Ensure that the HO2S is securely installed.
    • Inspect for corrosion on the terminals.
    • Test the terminal tension at the HO2S and at the PCM. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
    • Inspect for damaged wiring.

Did you find and correct the condition?

--

Go to Step 14

Go to Step 6

6

  1. Disconnect the HO2S.
  2. Jumper the HO2S low signal circuit on the PCM side to a known good ground.
  3. Observe the HO2S voltage on the Engine 1 Data List with a scan tool.

Does the scan tool indicate a voltage within the specified range?

350-550 mV

Go to Step 7

Go to Step 10

7

  1. Jumper the HO2S high and low signal circuits on the PCM side to a battery ground.
  2. Observe the HO2S voltage with a scan tool.

Does the scan tool indicate a voltage below the specified value?

200 mV

Go to Step 13

Go to Step 9

8

Important: Determine and correct the cause of the contamination before replacing a sensor. Inspect for the following conditions:

   • Fuel contamination
   • Use of an improper RTV sealant
   • Engine oil and coolant consumption

Replace the affected Heated Oxygen sensor. Refer to Heated Oxygen Sensor Replacement - Bank 1 Sensor 1 , and/or refer to Heated Oxygen Sensor Replacement - Bank 2 Sensor 1 .

Did you complete the replacement?

--

Go to Step 14

--

9
  1. Remove the jumper wire from the HO2S low signal circuit.
  2. Measure the voltage from the HO2S low signal circuit to a battery ground using the DMM J 39200 . Refer to Measuring Voltage in Wiring Systems.

Does the DMM indicate a voltage near the specified value?

5 V

Go to Step 12

Go to Step 11

10

Repair the HO2S high signal circuit for a short to ground or short to voltage. Refer to Heated Oxygen Sensor Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 14

--

11

Repair the open in the HO2S low signal circuit or repair the poor PCM connections. Refer to Heated Oxygen Sensor Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 14

--

12

Repair the HO2S high signal circuit for an open or repair the poor PCM connections. Refer to Heated Oxygen Sensor Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 14

--

13

Replace the affected HO2S. Refer to Heated Oxygen Sensor Replacement - Bank 1 Sensor 1 and/or Heated Oxygen Sensor Replacement - Bank 2 Sensor 1 .

Did you complete the replacement?

--

Go to Step 14

--

14
  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 15

Go to Step 2

15

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