2.0L DOHC
P0133Component Location:
General Description
The linear O2 sensor is mounted on the front side of the Catalytic Converter (warm-up catalytic converter) or in the front exhaust pipe. It detects a wide range of air/fuel ratios in the exhaust gas from the rich to lean regions. This linear O2 sensor produces a current that corresponds to a specific air/fuel ratio. The ECM monitors this signal and determines whether the air/fuel mixture is rich or lean. The ECM constantly monitors the linear O2 sensor and increases or decreases the fuel injection duration using this signal. This is called closed-loop fuel control operation.
DTC Description
The ECM monitors front oxygen sensor amplitude level and compares it to predetermined minimum amplitude value which could increase emission or disturb lambda control by the effect of aging on the oxygen sensor. The ECM sets DTC P0133 when the amplitude of oxygen sensor is equal to or less than minimum amplitude threshold.
DTC Detecting Condition:
Schematic Diagram:
Signal Waveform:
Monitor DTC Status
CAUTION: If any misfire, Purge Solenoid Valve, Mass Air Flow Sensor or O2 Sensor heater codes are present, DO ALL REPAIRS associated with those codes before proceeding with this troubleshooting tree.
1. Connect scan tool and select "Diagnostic Trouble Codes (DTCs)" mode
2. Press F5 (INFO) to select DTC information from the DTCs menu
3. Confirm that "DTC Readiness Flag" indicates "Complete". If not, drive the vehicle within conditions noted in the freeze frame data or enable conditions
4. Read "DTC Status" parameter
5. Is parameter displayed "History (Not Present) fault"?
CAUTION
- History (Not Present) fault : DTC occurred but has been cleared.
- Present fault : DTC is occurring at present time.
YES
a. Fault is intermittent caused by poor contact in the sensor's and/or ECM's connector or was repaired and ECM memory was not cleared. Thoroughly check connectors for loose or poor connection, bending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary and go to "Verification of Vehicle Repair" procedure
NO
a. Go to "System Inspection" procedure
System Inspection
Visual/Physical Inspection
1. Visually/physically inspect the following items:
- Ensure that the HO2S is securely installed.
- Check for corrosion on terminals
- Check for terminal tension (at the HO2S and at the ECM)
- Check for damaged wiring
- Check the HO2S ground circuit for a good connection
2. Check front and rear HO2S for connections being reversed. If HO2S connections reversed, switch connections properly.
3. Was a problem found in any of the above areas?
YES
a. Repair as necessary and go to "Verification of Vehicle Repair" procedure
NO
a. Go to "Air Leakage Inspection" procedure
Air Leakage Inspection
4. Visually/physically inspect the following items:
- Vacuum hoses for splits, kinks and improper connections.
- Exhaust system between HO2S and Three way catalyst for air leakage
- EVAP system for leakage
- PCV hose for proper installation
5. Was a problem found in any of the above areas?
YES
a. Repair as necessary and go to "Verification of Vehicle Repair" procedure
NO
a. Go to "Fuel Pressure Inspection" procedure
Fuel Pressure Inspection
6. Check the fuel for excessive water, alcohol, or other contaminants. Replace contaminated fuel as necessary.
7. Install a fuel pressure gauge
8. Inspect fuel pressure with engine idling at normal operating temperature.
Specification : 338-348 kPa (3.45-3.55 kg/sq.cm)
9. Is the fuel pressure within the specified value?
YES
a. Go to "Fuel Injector Inspection" procedure as below
NO
a. Repair as necessary refer to inspection note as below and go to "Verification Vehicle Repair" procedure
CAUTION
a.Check if fuel line pressure decreases when accelerating quickly
a. If it does, check fuel pump maximum pressure. If pressure is OK, check fuel line and filter for clogging
b. If fuel pressure is lower than specification : Check for fuel line pressure while pinching fuel return hose.
a. If pressure quickly increases, check pressure regulator
b. If pressure gradually increases, check for clogging between fuel pump and pressure regulator. If hose is not clogged, check fuel pump maximum pressure.
c. If fuel pressure is higher than specification : Is fuel line clogged?
a. If it is not, replace pressure regulator.
b. If it is, replace it
Fuel Injector Inspection
10. Ignition "OFF"
11. Check the fuel injectors for clogging or any restrictions
Specification : No clogging and restriction
12. Is the fuel injector OK?
YES
a. Go to "Component Inspection" procedure
NO
a. Repair as necessary and go to "Verification of Vehicle Repair" procedure
Component Inspection
1. Visually/physically inspect following items:
- Inspect the front HO2S for any silicon contamination. This contamination will be indicated by a white powdery coating and this will result in a but false voltage signal
- If contamination is evident on the HO2S, replace contaminated sensor and go to next step.
2. Warm up the engine to normal operating temperature and check that HO2S signal is active.
3. Connect Scantool and monitor the "O2 SNSR VOLT. (B1/S1)" parameter on the Scantool data list.
a. Test Condition : Engine "ON" & In Closed loop mode
4. Is sensor data near the specified value?
YES
a. Check for poor connection between ECM and component: backed out terminal, improper mating, broken locks or poor terminal to wire connection. Repair as necessary and go to "Verification of Vehicle Repair" procedure
NO
a. Substitute with a known-good HO2S and check for proper operation. If the problem is corrected, replace HO2S and then go to "Verification of Vehicle Repair" procedure
Verification of Vehicle Repair
After a repair, it is essential to verify that the fault has been corrected.
1. Connect scan tool and select "Diagnostic Trouble Codes (DTCs)" mode
2. Press 5 (INFO) and confirm that "DTC Readiness Flag" indicates "Complete". If not, drive the vehicle within conditions noted in the freeze frame data or enable conditions
3. Read "DTC Status" parameter
4. Is parameter displayed "History (Not Present) fault"?
YES
a. System performing to specification at this time. Clear the DTC
NO
a. Go to the applicable troubleshooting procedure.