Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
DTC Descriptor
DTC P0133: HO2S Slow Response Sensor 1Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
HO2S Sensor 1 Signal | P0131 | P0131 | P0132 | P0133 |
HO2S Sensor 2 Signal | P0137 | P0137 | P0138 | P0140 |
Low Reference | -- | P0131, P0137 | P0132, P0138 | -- |
Typical Scan Tool Data
Circuit | Short to Ground | Open | Short to Voltage |
|---|---|---|---|
Operating Conditions: Engine operating in Closed Loop. Parameter Normal Range: Fluctuates above and below 350-500 mV. | |||
Sensor Signal | 0-60 mV | 400-415 mV | 5000 mV |
Low Reference | -- | 400-415 mV | 5000 mV* |
* Internal ECM damage may occur if the circuit is shorted to B+. | |||
Circuit Description
The heated oxygen sensors (HO2S) are used for fuel control and catalyst monitoring. Each HO2S compares the oxygen content of the surrounding air with the oxygen content of the exhaust stream. When the engine is started, the control module operates in an Open Loop mode, ignoring the HO2S signal voltage while calculating the air-to-fuel ratio. The control module supplies the HO2S with a reference, or bias voltage of about 450 mV. While the engine runs, the HO2S heats up and begins to generate a voltage within a range of 0-1,000 mV. This voltage will fluctuate above and below the bias voltage. Once sufficient HO2S voltage fluctuation is observed by the control module, Closed Loop is entered. The control module uses the HO2S voltage to determine the air-to-fuel ratio. An HO2S voltage that increases above bias voltage toward 1,000 mV indicates a rich fuel mixture. An HO2S voltage that decreases below bias voltage toward 0 mV indicates a lean fuel mixture.
The heating elements inside each HO2S heat the sensor to bring the sensor up to operating conditions faster. This allows the system to enter Closed Loop earlier and the control module to calculate the air-to-fuel ratio sooner.
The HO2S utilizes the following circuits:
| • | A signal circuit |
| • | A low reference circuit |
| • | An ignition 1 voltage circuit |
| • | A heater control circuit |
Conditions for Running the DTC
| • | DTC P0030 and P0036 are not set. |
| • | The fuel system is in Closed Loop. |
| • | The engine control module (ECM) command of the evaporative emission (EVAP) canister purge solenoid is less than 100 percent. |
| • | The engine coolant temperature (ECT) is more than 70°C (158°F). |
| • | The vehicle speed is between 65-75 km/h (40-46 mph). |
| • | The engine speed is between 2,144-2,464 RPM. |
| • | The air flow into the engine is between 23-43 kg/h. |
| • | The engine is running for more than 320 seconds. |
| • | The DTC runs once per ignition cycle once the above conditions are met. |
Conditions for Setting the DTC
Euro III Emissions
| • | The ECM detects that the average rich to lean response is more than 0.8 second. |
| • | The ECM detects that the average rich to lean response is more than 1.02 seconds or the lean to rich response is more than 0.77 second. |
Euro IV Emissions
| • | The ECM detects that the average rich to lean response is more than 1.04 seconds or the lean to rich response is more than 0.75 second. |
| • | The ECM detects a difference between the rich to lean time is more than 1 second, or the ECM detects a difference between the lean to rich time is less than 1 second. |
Action Taken When the DTC Sets
DTC P0133 is a Type B DTC.
Conditions for Clearing the MIL/DTC
DTC P0133 is a Type B DTC.
Reference Information
Schematic Reference
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
- Engine running, observe the DTC Information with a scan tool. Verify no DTCs are set.
- Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
| ⇒ | If any DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle to diagnose the applicable DTC. |
Circuit/System Testing
- Verify the following conditions do not exist:
- If all circuits test normal, test or replace the HO2S sensor.
| • | An exhaust leak near the HO2S--Refer to Symptoms - Engine Exhaust. |
| • | The HO2S is not securely installed |
| • | Corrosion on the HO2S terminals |
| • | Poor terminal tension at the HO2S and at the ECM |
| • | HO2S wiring damage |
| • | Fuel that is contaminated--Refer to Alcohol/Contaminants-in-Fuel Diagnosis. |
| • | Incorrect RTV sealant |
| • | Engine oil consumption--Refer to Symptoms - Engine Mechanical for the 0.8L engine. |
| • | Engine coolant consumption--Refer to Loss of Coolant. |
| ⇒ | If you find any of the above conditions, repair as necessary. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for ECM replacement, setup, and programming |
