P0133
Fuel System - Troubleshooting - 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 PCM monitors this signal and determines whether the air/fuel mixture is rich or lean. The PCM 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 PCM 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 PCM sets DTC P0133 when the amplitude of oxygen sensor is equal to or less than minimum amplitude threshold.
DTC Detecting Condition:
MONITOR DTC STATUS
NOTE: 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"?
NOTE:
1. History (Not Present) fault : DTC occurred but has been cleared.
2. Present fault : DTC is occurring at present time.
YES - Fault is intermittent caused by poor contact in the sensor's and/or PCM's connector or was repaired and PCM 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 - Go to next step.
VISUAL / PHYSICAL INSPECTION
1. Visually/physically inspect the following items:
A. Ensure that the HO2S is securely installed.
B. Check for corrosion on terminals.
C. Check for terminal tension (at the HO2S and at the PCM).
D. Check for damaged wiring.
E. 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 - Repair as necessary and go to "Verification of Vehicle Repair" procedure.
NO - Go to "Air Leakage Inspection" procedure.
AIR LEAKAGE INSPECTION
1. Visually/physically inspect the following items:
A. Vacuum hoses for splits, kinks and improper connections.
B. Exhaust system between HO2S and Three way catalyst for air leakage.
C. EVAP system for leakage.
D. PCV hose for proper installation.
2. Was a problem found in any of the above areas?
YES - Repair as necessary and go to "Verification of Vehicle Repair" procedure.
NO - Go to "Fuel Pressure Inspection" procedure.
FUEL PRESSURE INSPECTION
1. Check the fuel for excessive water, alcohol, or other contaminants. Replace contaminated fuel as necessary.
2. Install a fuel pressure gage.
3. Inspect fuel pressure with engine idling at normal operating temperature.
Test Condition : Ignition "ON" & Engine "ON" & Vacuum hose disconnected at Idle Specification : 350 kPa (3.5 kg/sq.cm, 49.8 psi)
4. Is the fuel pressure within the specified value?
YES - Go to "Fuel Injector Inspection" procedure.
NO - Repair as necessary refer to inspection note. and go to "Verification of Vehicle Repair" procedure.
NOTE:
1. Check if fuel line pressure decreases when accelerating quickly.
1. If it does, check fuel pump maximum pressure. If pressure is OK, check fuel line and filter for clogging.
2. If fuel pressure is lower than specification : Check for fuel line pressure while pinching fuel return hose.
1. If pressure quickly increases, check pressure regulator.
2. If pressure gradually increases, check for clogging between fuel pump and pressure regulator. If hose is not clogged, check fuel pump maximum pressure.
3. If fuel pressure is higher than specification : Is fuel line clogged?
1. If it is not, replace pressure regulator.
2. If it is, replace it.
FUEL INJECTOR INSPECTION
1. Ignition "OFF"
2. Check the fuel injectors for clogging or any restrictions. Specification : No clogging and restriction
3. Is the fuel injector OK?
YES - Go to "Component Inspection" procedure.
NO - Repair as necessary and go to "Verification of Vehicle Repair" procedure.
COMPONENT INSPECTION
1. Visually/physically inspect following items:
A. 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.
B. 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.
Test Condition : Engine "ON" & In Closed loop mode
4. Is sensor data near the specified value??
YES - Check for poor connection between PCM 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 - 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 F5(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 - System performing to specification at this time. Clear the DTC.
NO - Go to the applicable troubleshooting procedure.
Schematic Diagram:
