Circuit Description
The powertrain control module (PCM) monitors the heated oxygen sensor (HO2S) activity for 100 seconds. During this monitoring period, the PCM counts the number of times that the HO2S switches from rich to lean, and from lean to rich. A DTC P1133 or P1153 sets when the PCM determines that the HO2S did not switch enough times.
A lean to rich switch is determined when the HO2S voltage changes from less than 300 mV to more than 600 mV. A rich to lean switch is determined when the HO2S voltage changes from more than 600 mV to less than 300 mV.
Conditions for Running the DTC
| • | DTCs P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0131, P0132, P0134, P0135, P0151, P0152, P0154, P0155, P0300, P0351, P0401, P0404, P0405, P0440, P0442, P0446, P0452, P0453, P1258, P1404, P1441 are not set. |
| • | The engine run time is more than 160 seconds. |
| • | The engine speed is between 1,100 RPM and 3,000 RPM. |
| • | The ECT sensor is more than 57°C (135°F). |
| • | The MAF sensor is between 15 g/s and 55 g/s. |
| • | The EVAP purge solenoid command is more than 0 percent. |
| • | The loop status is Closed |
| • | The TP sensor is more than 5 percent. |
| • | The ignition 1 signal is between 9 and 18 volts. |
Conditions for Setting the DTC
The PCM determines that within 100 seconds the HO2S lean to rich switches are less than 1, and the rich to lean switches are less than 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
Important: Before you service the PCM, remove any debris from the PCM connector surfaces. Inspect the PCM connector gaskets when diagnosing or replacing the PCM. Ensure that the gaskets are installed correctly. The gaskets prevent water intrusion into the PCM.
| • | Inspect the HO2S signal circuit for being shorted to a PCM ground. The HO2S signal circuit shorted to a PCM ground sets a switching DTC. |
| • | A malfunction in the HO2S heater circuits will cause a DTC P1133 to set. Check the HO2S heater circuits for intermittent opens, or for loose connections. |
| • | An oxygen supply inside the HO2S is necessary for proper operation. This oxygen supply is provided through the HO2S wires. Inspect all HO2S wires and connections for breaks or for contamination. Refer to Heated Oxygen Sensor (HO2S) Wiring Repairs in Wiring Systems. |
| • | Using the Freeze Frame/Failure Records may help to locate an intermittent condition. If you cannot duplicate the DTC , use the information in the Freeze Frame/Failure Records to help to determine how many miles have occurred since the DTC set. Use the Fail Counter and the Pass Counter in order to determine how many ignition cycles have occurred since the diagnostic reported a pass or a fail. In order to isolate when the DTC failed, operate vehicle within the same Freeze Frame conditions that you observed. These conditions include: |
| - | The RPM |
| - | The vehicle load |
| - | The vehicle speed |
| - | The temperature |
For an intermittent condition , refer to Symptoms - Engine Controls .
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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This step determines if the fault is present. This test may take 5 minutes for the diagnostic to run. For any test that requires probing the PCM or a component harness connector, use the J 35616 connector test adapter kit . Using this kit prevents damage to the harness connector terminals.
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When DTCs P1133 and P1153 are set at the same time, fuel contamination is likely.
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An exhaust leak 6-12 inches away from the HO2S can cause a DTC to set.
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This step tests the HO2S for being tight and determines if the connectors and the circuits are OK.
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This step tests the integrity of the HO2S low signal circuit to the PCM.
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This step tests the integrity of the HO2S high signal circuit to the PCM.
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Certain room temperature vulcanizing (RTV) silicon gasket materials release vapors that can contaminate the HO2S. Silicon in the fuel can also cause contamination. If the sensors appear silicon-contaminated, and if all the silicon sealant is a non-silicon base, advise the customer to try a different fuel company. A missing fuel filler restrictor may indicate that the customer has 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 | |||||||||
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Important: If any DTCs are set, except P1133 or P1153, refer to those DTCs before proceeding with this diagnostic table.
Did DTC P1133 or P1153 fail this ignition? | -- | Go to Step 3 | Go to Diagnostic Aids | |||||||||
Did both DTC P1133 and P1153 fail this ignition? | -- | Go to Step 8 | Go to Step 4 | |||||||||
Did you find and correct the condition? | -- | Go to Step 14 | Go to Step 5 | |||||||||
Inspect the following items:
Did you find and correct the condition? | -- | Go to Step 14 | Go to Step 6 | |||||||||
Does the scan tool indicate that the voltage is within the specified range? | 350-550 mV | Go to Step 7 | Go to Step 10 | |||||||||
Does the scan tool indicate that the voltage is less than the specified value? | 200 mV | Go to Step 13 | Go to Step 9 | |||||||||
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Important: Before you replace a sensor, determine and correct the cause of the
contamination. Inspect for the following conditions:
Replace the affected heated oxygen sensor (HO2S). Refer to Heated Oxygen Sensor Replacement - Bank 1 Sensor 1 or Heated Oxygen Sensor Replacement - Bank 2 Sensor 1 . Did you complete the action? | -- | Go to Step 14 | -- | |||||||||
9 |
Does the DMM indicate a voltage near the specified value? | 5 V | Go to Step 12 | Go to Step 11 | ||||||||
10 | Repair the high signal circuit for a short to ground or for a short to voltage. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | Go to Step 14 | -- | ||||||||
11 | Repair the open HO2S low circuit, or repair the faulty PCM connections. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | Go to Step 14 | -- | ||||||||
12 | Repair the HO2S high signal circuit for an open, or repair the poor PCM connections. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | Go to Step 14 | -- | ||||||||
13 | Replace the appropriate HO2S. Refer to Heated Oxygen Sensor Replacement - Bank 1 Sensor 1 or Heated Oxygen Sensor Replacement - Bank 2 Sensor 1 . Is the action complete? | -- | Go to Step 14 | -- | ||||||||
14 |
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? | -- | System OK | |||||||||
