Circuit Description
The powertrain control module (PCM) continuously monitors the heated oxygen sensor (HO2S) activity for 120 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 can be determined. If the average response time is too slow, a DTC P0133 will be set. A lean to rich transition is indicated when the HO2S voltage changes from less than 300 mV to greater 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
| • | No TP sensor, EVAP system, misfire, IAT sensor, MAP sensor, fuel trim, fuel injector circuit, EGR Pintle Position, ECT sensor, HO2S heater circuit sensor 1, CKP, or MAF sensor DTC present. |
| • | Engine has been running in Closed Loop fuel control for at least 60 seconds. |
| • | Engine speed is between 1000 RPM and 3000 RPM. |
| • | Engine Coolant Temperature greater than 50°C (122°F). |
| • | Mass Air Flow 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 130 milliseconds or rich to lean average transition response time during the sample period was longer than 110 milliseconds.
Action Taken When the DTC Sets
| • | The PCM will illuminate the malfunction indicator lamp (MIL) during the second consecutive trip in which the diagnostic test has been run and failed. |
| • | The PCM will store conditions which were present when the DTC set as Freeze Frame/Failure Records data. |
Conditions for Clearing the MIL/DTC
| • | The PCM will turn OFF the malfunction indicator lamp (MIL) during the third consecutive trip in which the diagnostic has run and passed. |
| • | The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction. |
| • | The DTC can be cleared by using a scan tool. |
Diagnostic Aids
Check for the following conditions:
| • | Poor Connections at PCM. |
| Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection. |
| • | Damaged harness. |
| Inspect the wiring harness for damage. If the harness appears to be OK, observe the H02S 1 display on the scan tool while moving connectors and wiring harnesses related to the sensor. A change in the display will indicate 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
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 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 | Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | ||||||||||
|
Important: If any DTCs are set, except P1133 or P1134, refer to those DTCs before proceeding with this diagnostic table.
Des the scan tool indicate DTC P0133 failed this ignition? | -- | Go to Diagnostic Aids | ||||||||||
Did the scan tool also indicate DTC P1133 or P1134 failed this ignition? | -- | |||||||||||
4 |
Was a problem found? | -- | ||||||||||
5 | Visually/physically inspect the following items:
Was a problem found in any of the above areas? | -- | ||||||||||
6 |
Does the scan tool indicate voltage near the specified value? | 450 mV | ||||||||||
7 |
Does the scan tool indicate voltage less than 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 heated oxygen sensor(s). Refer to Heated Oxygen Sensor Replacement - Sensor 1 or Heated Oxygen Sensor Replacement - Sensor 2 . Is the action complete? | -- | -- | |||||||||
9 | Repair the condition as necessary. Is the action complete? | -- | -- | |||||||||
10 | Repair open or high resistance HO2S 1 low signal circuit or grounded HO2S 1 high signal circuit . Refer to Wiring Repairs . Is the action complete? | -- | -- | |||||||||
11 | Repair open HO2S 1 high signal circuit or malfunctioning PCM connections. Refer to Wiring Repairs or Repairing Connector Terminals . Is the action complete? | -- | -- | |||||||||
12 | Replace HO2S 1. Refer to Heated Oxygen Sensor Replacement - Sensor 1 . Is the action complete? | -- | -- | |||||||||
13 |
Does the scan tool indicate DTC P0133 failed this ignition? | -- | System OK |
