P0133
DTC P0133 HO2S CIRCUIT SLOW RESPONSE (BANK 1 / SENSOR 1)Component Location:
GENERAL DESCRIPTION
The HO2S is used to supply the ECM with information regarding the composition of the air/fuel mixture. The HO2S is positioned in the exhaust pipe ahead of the TWC. To measure the oxygen content, the HO2S requires a supply of ambient air as a reference. Since this is supplied through the wiring, the lead must not be clamped or damaged in any other way. The HO2S produces a voltage that varies between 0.1 V and 0.9 V under normal operating conditions. The Engine Control Module (ECM) monitors this voltage and determines if the exhaust gas is lean or rich. If the voltage input at the ECM is under approx. 0.45 V the exhaust is lean, and if the voltage input is over approx. 0.45 V the exhaust is rich. The ECM constantly monitors the HO2S signal during closed loop operation and compensates for a rich or lean condition by decreasing or increasing injector pulse width as necessary.
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
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 F4(DTAL) 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:
- History (Not Present) fault: DTC occurred but has been cleared.
- Present fault: DTC is occuring at present time.
YES: 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: Go to next step as below.
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: 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:
- 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.
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 : Engine "ON" & Vacuum hose disconnected at Idle.
Specification : 320-340 kPa (3.26-3.47 kg/sq.cm, 46-49 psi)
4. Is the fuel pressure within the specified value?
YES: Go to "Fuel Injector Inspection" procedure as below.
NO: Repair as necessary refer to inspection note as below and go to "Verification of Vehicle Repair" procedure.
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:
- 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 "FR OXYGEN SNSR-B1" parameter on the Scantool data list.
Test Condition : Engine "ON"
Specification : Verify signal is switching from rich(above 0.45 V) to lean(below 0.45 V) a minimum of 3 times in 10 seconds (voltage will vary between 0.1 and 0.9 V).
4. Is sensor switching properly?
YES: 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: Check HO2S for contamination, deterioration, or damage. 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 F4(DTAL) 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.