P0133
DTC P0133
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.
DTC Descriptors
DTC P0133
- HO2S Slow Response Sensor 1
Circuit Description
The wide band heated oxygen sensor (HO2S) measures the amount of oxygen in the exhaust system and provides more information than the switching style HO2S. The wide band sensor consists of an oxygen sensing cell, an oxygen pumping cell, and a heater. The exhaust gas sample passes through a diffusion gap between the sensing cell and the pumping cell. The engine control module (ECM) supplies a voltage to the HO2S and uses this voltage as a reference to the amount of oxygen in the exhaust system. An electronic circuit within the ECM controls the pump current through the oxygen pumping cell in order to maintain a constant voltage in the oxygen sensing cell. The ECM monitors the voltage variation in the sensing cell and attempts to keep the voltage constant by increasing or decreasing the amount of current flow, or oxygen ion flow, to the pumping cell. By measuring the amount of current required to maintain the voltage in the sensing cell, the ECM can determine the concentration of oxygen in the exhaust. The HO2S voltage is displayed as a lambda value. A lambda value of 1 is equal to a stoichiometric air fuel ratio of 14.7:1. Under normal operating conditions, the lambda value will remain around 1. When the fuel system is lean, the oxygen level will be high and the lambda signal will be high or more than 1. When the fuel system is rich, the oxygen level will be low, and the lambda signal will be low or less than 1. The ECM uses this information to maintain the correct air/fuel ratio.
Conditions for Running the DTCs
* Before the ECM can report DTC P0133 failed, DTCs P0121, P0122, P0123, P0221, P0222, P0223, P0335, P0336, P0338, and P2237 must run and pass.
* DTCs P0030, P0031, P0032, P0053, P0130, P0131, P0132, P0135, P0442, P0443, P0446, P0455, P0458, P0459 P167A, P2096, P2097, P2231, P2243, P2251, P2297, and P2626 are not set.
* The HO2S is at operating temperature.
* The fuel trim is enabled.
* The HO2S is between 0.94-1.06 lambda.
* The engine speed is between 1,480-2,520 RPM.
* The volumetric efficiency is between 15.7-50.2 percent.
* The change in volumetric efficiency is less than 3 percent.
* The evaporative emission (EVAP) purge is not active, or the ECM determines the EVAP hydrocarbon (HC) concentration is less than a predetermined threshold.
* The long term fuel trim correction is active.
* DTC P0133 runs continuously once the above conditions are met for approximately 10 minutes.
Conditions for Setting the DTCs
* The ECM has determined that the dynamic value of the affected HO2S is less than a predetermined threshold.
* The above condition is exists for greater than 4 seconds.
Action Taken when the DTCs Set
DTC P0133 is a Type B DTC.
Conditions for Clearing the MIL/DTCs
DTC P0133 is a Type B DTC.
Diagnostic Aids
The following table illustrates the ECM connector locations:
* The front wide band sensor does not toggle or switch like a switching HO2S. The front HO2S signal will be relatively stable for an idling engine.
* The following table illustrates the typical voltages for the HO2S circuits:
Reference Information
Schematic Reference
Engine Controls Schematics (Electrical Diagrams)
Connector End View Reference
Component Connector End Views (Connector Views)
Electrical Information Reference
* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions (Diagnostic Trouble Code Descriptions)
Scan Tool Reference
Control Module References (Programming and Relearning) for scan tool information
Circuit/System Verification
1. Ignition ON, observe the scan tool DTC information. Verify no other DTCs are set.
• If any other DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle (Diagnostic Trouble Code Descriptions).
2. 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 are captured in the Freeze Frame/Failure Records Data List.
Circuit/System Testing
1. Verify that none of the following conditions exist:
* Inspect the HO2S 1 for being secure
* Lean or rich fuel injectors-Refer to Fuel Injector Balance Test with Special Tool (Fuel Injector Balance Test With Special Tool) or Fuel Injector Balance Test with Tech 2 (Fuel Injector Balance Test With Tech 2)
* Water intrusion in the HO2S harness connector
* HO2S wiring harness damage
* Incorrect RTV sealant
* Incorrect fuel system pressure-Refer to Fuel System Diagnosis (Component Tests and General Diagnostics)
* Fuel that is contaminated-Refer to Alcohol/Contaminants-in-Fuel Diagnosis (w/o Special Tool) (Alcohol/Contaminants-in-Fuel Diagnosis (Without Special Tool))Alcohol/Contaminants-in-Fuel Diagnosis (w/ Special Tool) (Alcohol/Contaminants-In-Fuel Diagnosis (With Special Tool))
* Fuel saturation of the evaporative emission (EVAP) canister
* Exhaust leaks near the HO2S-Refer to Exhaust Leakage (Exhaust Leakage)
* Engine vacuum leaks
* Engine oil consumption-Refer to Oil Consumption Diagnosis (Component Tests and General Diagnostics)
* Engine coolant consumption-Refer to Loss of Coolant (Loss of Coolant)
• If you find any of the above conditions, repair as necessary.
2. If all conditions test normal, replace the HO2S 1.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Heated Oxygen Sensor 1 Replacement (Service and Repair)
* Control Module References (Programming and Relearning) for engine control module replacement, setup, and programming