P1133

Diagnostic Chart:

Wiring Diagram:

Circuit Description
The VCM supplies a voltage of about 0.45 volt between the HO2S High and HO2S Low circuits. (If measured with a 10 megohm digital voltmeter, this may read as low as 0.32 volt.) The Heated Oxygen Sensor (HO2S 1) varies the voltage within a range of about 1.0 volt if the exhaust is rich, down through about 0.10 volt if the exhaust is lean.

The sensor is like an open circuit and produces no voltage when it is below 360°C (600°F). An open oxygen sensor circuit or cold oxygen sensor causes an Open Loop operation.

The HO2S heater provides for a faster sensor warm-up which allows the sensor to become active in a shorter period of time and remain active during a long extended idle.

The DTC P1133 determines if the HO2S functioning properly by monitoring the number of the L/R and the R/L switches. The DTC P1133 is a type B DTC.

Conditions for Setting the DTC

^ L/R switches less than 50.
^ R/L switches less than 50.
^ No Throttle Position (TP) sensor DTCs.
^ No EVAP DTCs.
^ No IAT sensor DTCs.
^ No MAP DTCs.
^ No ECT sensor DTCs.
^ No MAF sensor DTCs.
^ No intrusive test in progress.
^ No device controls active.
^ The system voltage is at least 9.0 volts.

Response Test Enable

^ Closed Loop.
^ Closed loop low MAP not active.
^ DTCs P0131, P0132, P0134, and DTC P0135 not active.
^ Engine run time is greater than 75 seconds.
^ MAF is at least 15 g/s and no more than 55 g/s.
^ Engine speed is at least 1100 RPM and no more than 3000 RPM.
^ The EVAP canister purge duty cycle is at least 0.0%.
^ The above conditions are met for a time greater than 2 seconds.

Action Taken When DTC Sets
The VCM turns on the Malfunction Indicator Lamp (MIL) after the second test failure.

Conditions for Clearing the MIL/DTC
The VCM turns the MIL off after 3 consecutive driving trips without a fault condition present. A history DTC will clear if no fault conditions have been detected for 40 warm-up cycles (coolant temperature has risen 40°F from the start-up coolant temperature and the engine coolant temperature exceeds 160°F during that same ignition cycle) or the scan tool clearing feature has been used.

Diagnostic Aids
Check the HO2S heater operation.

NOTE: Never solder the HO2S wires. For proper wire and connector repairs, refer to Wiring Repairs in Engine Electrical.

Test Description
The numbers below refer to the step numbers in the diagnostic table.

2. This step checks for other DTCs.
4. This step checks for any physical damage to the engine components and the converter.
6. This step checks the fuel injector and isolates the HO2S.