Circuit Description
The powertrain control module (PCM) continuously monitors the heated oxygen sensor (HO2S) activity for 100 seconds. During the monitoring period the PCM counts the number of times that the a rich to lean and lean to rich response is indicated and adds the amount of time it took to complete all transitions. With this information, an average time for each transition may be determined. If the average response time is too slow, a DTC P0133 is set. A lean to rich transition is indicated when the HO2S voltage changes from less than 300 mV to more than 600 mV. A rich to lean transition is indicated when the HO2S voltage changes from more than 600 mV to less than 300 mV. An HO2S that responds too slowly is likely to be malfunctioning and should be replaced.
Conditions for Running the DTC
| • | None of the following DTCs are present: |
| - | Throttle position (TP) sensor DTCs |
| - | Evaporative emissions (EVAP) DTCs |
| - | Intake air temperature (IAT) sensor DTCs |
| - | Manifold absolute pressure (MAP) sensor DTCs |
| - | Exhaust gas recirculation (EGR) pintle position DTCs |
| - | Engine coolant temperature (ECT) sensor DTCs |
| - | Crankshaft position (CKP) sensor DTCs |
| - | Mass air flow (MAF) sensor DTCs |
| - | Misfire DTCs |
| - | Fuel trim DTCs |
| - | Fuel injector circuit DTCs |
| • | The engine is running in closed loop fuel control for at least 60 seconds. |
| • | The engine speed is between 1000 RPM and 3000 RPM. |
| • | The ECT is more than 50°C (122°F). |
| • | The MAF is between 10 g/s and 30 g/s. |
Conditions for Setting the DTC
H02S 1 lean to rich average transition response time during the sample period was longer than 145 milliseconds or rich to lean average transition response time during the sample period was longer than 135 milliseconds.
Action Taken When the DTC Sets
| • | The PCM illuminates the malfunction indicator lamp (MIL) during the second consecutive trip in which the diagnostic test has run and failed. |
| • | The PCM stores the conditions which were present when the DTC set as Freeze Frame and Fail Records data. |
Conditions for Clearing the MIL/DTC
| • | The PCM turns the MIL off during the third consecutive trip in which the diagnostic has run and passed. |
| • | The history DTC clear after 40 consecutive warm-up cycles have occurred without a malfunction. |
| • | The DTC may be cleared by using the scan tool Clear Info function or by disconnecting the PCM battery feed. |
Diagnostic Aids
Inspect for the following conditions:
| • | A faulty connection at the PCM. Inspect the harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and faulty terminal to wire connections. |
| • | Inspect the wiring harness for damage. If the harness appears to be OK, observe the H02S 1 display on the scan tool while moving the connectors and the wiring harnesses related to the sensor. A change in the display indicates the location of the malfunction. If DTC P0133 cannot be duplicated, reviewing the Fail Records vehicle mileage since the diagnostic test last failed may help determine how often the condition that caused the DTC to be set occurs. This may assist in diagnosing the condition. |
Test Description
The number(s) below refer to the step number(s) on the Diagnostic Table:
-
Verifies that the malfunction is currently present.
-
HO2S transition time, ratio, and switching DTCs set for multiple sensors indicate probable contamination. Before replacing the sensors, isolate and correct the source of the contamination to avoid damaging the replacement sensors.
Step | Action | Value(s) | Yes | No | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | ||||||||||
|
Important: If any DTCs other than P1133 or P1134 are set, refer to those DTC Tables before proceeding with this diagnostic.
Does the scan tool indicate DTC P0133 Failed This Ign? | -- | Go to Diagnostic Aids | ||||||||||
Did the scan tool also indicate DTC P1133 or P1134 Failed This Ign? | -- | |||||||||||
4 |
Was a problem found? | -- | ||||||||||
5 | Visually/physically inspect the following items:
Was a problem found in any of the above areas? | -- | ||||||||||
6 |
Is the voltage near the specified value? | 450 mV | ||||||||||
7 |
Is the voltage less than the specified value? | 300 mV | ||||||||||
8 |
Notice: Correct the source of the oxygen sensor contamination before replacing
the sensor in order to prevent future contamination. Typical contamination
sources include the following:
Replace the affected HO2S. Did you complete the repair? | -- | -- | |||||||||
9 | Repair the condition as necessary. Did you complete the repair? | -- | -- | |||||||||
10 | Repair an open HO2S 1 low signal circuit or a grounded HO2S 1 high signal circuit. Refer to Heated Oxygen Sensor Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | -- | |||||||||
11 | Repair an open HO2S 1 high signal circuit or faulty PCM connections. Refer to Heated Oxygen Sensor Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | -- | |||||||||
12 | Replace the HO2S 1. Refer to Heated Oxygen Sensor Replacement . Did you complete the repair? | -- | -- | |||||||||
13 |
Does the scan tool indicate DTC P0133 Failed This Ign? | -- | System OK |
