P0133
Diagnostic Chart:
Diagnostic Chart (cont'd):
Electrical Diagram:
CIRCUIT DESCRIPTION
The PCM continuously monitors the Heated Oxygen Sensor (HO2S) activity for 100 seconds. During the monitoring period the PCM counts the number of times that a rich to lean and a lean to rich response is indicated. Then, the PCM 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 300mV to greater than 600mV. A rich to lean transition is indicated when the HO2S voltage changes from greater than 600 mV to less than 300mV. An HO2S that responds too slowly is likely to be faulty and should be replaced.
CONDITIONS FOR SETTING THE DTC
- No active transmission, Throttle Position (TP) sensor, EVAP system, EGR, misfire, IAT sensor, MAP sensor, fuel trim, fuel injector circuit, EVAP solenoid 0DM, ECT sensor, or MAF sensor DTC(s) present.
- DTC P0135 (02 Heater) not set.
- The engine has been running in closed loop for at least 2 minutes.
- Engine speed is between 1000 RPM and 3000 RPM.
- Engine Coolant Temperature greater than 75°C (167°F).
- Mass Air Flow between 15 gm/s and 29 gm/s.
- Bank 1 HO2S 1 lean to rich or rich to lean average transition response time was longer than 90 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 and Fail Records data.
CONDITIONS FOR CLEARING THE MIL/DTC
- The PCM will turn the MIL OFF during the third consecutive trip in which the diagnostic has been run and passed.
- The history DTC will clear after 40 consecutive warm-up cycles have occurred without a fault.
- The DTC can be cleared by using the scan tool Clear Info function or by disconnecting the PCM battery feed.
DIAGNOSTIC AIDS
Check for the following conditions:
- Poor connection 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 Bank 1 HO2S 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 fault. If DTC P0133 cannot be duplicated, Review the Fail Records vehicle mileage since the diagnostic test last failed. This may help determine how often the condition that caused the DTC to be set occurs.
TEST DESCRIPTION
Number(s) below refer to the Step number(s) on the Diagnostic Table:
2. This step verifies that the fault is currently present.
3. HO2S transition time, ratio mean volts 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.