P0133 Slow response of the oxygen sensor circuit

OBD-2 code - P0133 - Technical description

P0123 - Slow response oxygen sensor circuit (bank1, sensor1)

Bank 1 Sensor 1 is the sensor used by the computer (ECM) to monitor the amount of oxygen leaving the engine. The ECM uses the O2 sensor signal to adjust the fuel/air ratio in the engine. The air-fuel ratio is controlled by the engine control unit to regulate fuel consumption and limit the amount of air pollutants escaping from the engine. The O2 sensor will tell the ECM the air-fuel ratio by sending a voltage reading back to the ECM.

What does trouble code P0123 mean?

This is considered a generic transmission DTC. This means that this definition is the same for all makes and models of OBD-II vehicles, however, the specific repair steps may differ from vehicle to vehicle.

This DTC applies to the front oxygen sensor on block 1.

This code indicates that the engine air-fuel ratio is not being regulated by the oxygen sensor or ECM signal as expected, or is not being regulated as often as expected after the engine has warmed up or during normal engine operation.

Symptoms

You will most likely not notice any handling problems, although there may be symptoms.

• Engine light on (or service engine warning light)
• High fuel consumption
• Excess smoke from the exhaust pipe

Causes of the P0123 code

The P0133 code may mean that one or more of the following events have occurred:

• Oxygen sensor defective
• Broken / worn sensor wiring
• There is an exhaust leak
• Faulty front oxygen sensor, bank 1.
• Heated Front Oxygen Sensor Wiring Harness Bank 1 Open or Shorted
• Electrical connection to front heated oxygen circuit 1
• Insufficient fuel pressure
• Defective fuel injectors
• Intake air leak may be defective
• Exhaust leaks

Possible solutions

The simplest thing is to reset the code and see if it comes back.

If the code returns, the problem is most likely in the bank 1 front oxygen sensor. You will most likely need to replace it, but you should also consider the following possible solutions:

• Check and repair exhaust leaks.
• Check for wiring problems (shorted, frayed wires)
• Check the frequency and amplitude of the oxygen sensor (advanced)
• Check oxygen sensor for wear / contamination, replace if necessary.
• Check for air inlet leaks.
• Check the MAF sensor for proper operation.

P0133 BRAND SPECIFIC INFORMATION

• P0133 ACURA Circuit Slow Response Bank 1 Sensor 1
• P0133 AUDI HO2S11 Sensor Circuit Slow Response
• P0133 BUICK HO2S Slow response bank 1 sensor 1
• P0133 CADILLAC HO2S Slow response bank 1 sensor 1
• P0133 CHEVROLET HO2S Slow response bank 1 sensor 1
• P0133 CHRYSLER O2 Sensor Circuit Slow Response Bank 1 Sensor
• P0133 DODGE O2 Sensor Circuit Slow Response Sensor 1 Sensor 1
• P0133 FORD Sensor Slow Response Bank 1 Sensor
• P0133 GMC HO2S Slow Response Bank 1 Sensor 1
• P0133 HONDA O2 Sensor Circuit Slow Response Bank 1 Sensor 1
• P0133 HYUNDAI Sensor Circuit Slow Response Bank 1 Sensor 1
• P0133 INFINITI-2 Air Fuel Ratio Circuit Slow Response Bank 1 Sensor 1
• P0133 INFINITI Sensor Circuit Low Response Bank 1 Sensor 1
• P0133 ISUZU HO2S Slow response sensor 1
• P0133 JAGUAR O2 Sensor 1 Sensor Circuit Slow Response 1
• P0133 JEEP OEP Sensor 1 Sensor Circuit 1 Slow
• P0133 Slow response circuit KIA HO2S11
• P0133 LEXUS HO2S11 Circuit Slow Response
• P0133 LINCOLN Sensor 1 Low pressure sensor circuit 1
• P0133 MAZDA HO2S Circuit Slow Response
• P0133 MERCEDES-BENZ O2 Sensor Circuit Slow Response Bank 1 Sensor 1
• P0133 MERCURY Circuit Slow Response Sensor Bank 1 Sensor
• P0133 MITSUBISHI Heated 1-4 Front Oxygen Sensor Circuit Slow Response
• P0133 NISSAN-2 Air Fuel Ratio Circuit Slow Response Bank 1 Sensor 1
• P0133 NISSAN Sensor Slow Response Bank 1 Sensor 1
• P0133 PONTIAC HO2S Slow Response Bank 1 Sensor 1
• P0133 SATURN HO2S Oxygen Sensor Slow Response Bank 1 Sensor 1
• P0133 SCION Oxygen Sensor Circuit Slow Response Bank 1 Sensor 1
• P0133 SUBARU HO2S11 Circuit Slow Response
• P0133 SUZUKI Oxygen Sensor Circuit Slow Response Bank 1 Sensor 1
• P0133 Low response circuit TOYOTA HO2S11
• P0133 HO2S11 VOLKSWAGEN Sensor Circuit Slow Response

How does a technician diagnose code P0133?

• Visually inspects the wires associated with the O2 sensor for wear and contamination with contaminants such as oil.
• Measures the output voltage of the O2 sensor using a scan tool or multimeter.
• Visually inspects sensor base for soot, thermal shock, or oil deposits.
• Checks air intake and vacuum hoses for leaks

Common Mistakes When Diagnosing Code P0133

• Overlooking the fact that a dirty MAF sensor can cause the O2 sensor circuit to respond slowly.
• Do not clean the wires and electrical terminals of the O2 sensor
• Losing sight of the fact that a leaky vacuum line or a leaky intake manifold can cause erroneous O2 sensor voltage readings. Voltage readings that can set code P0133

How serious is the P0133 code?

This particular code can be harmful to the environment as the O2 sensor is used to minimize the amount of harmful pollutants emitted by the engine. The O2 sensor keeps pollutants to a minimum by adjusting the air-fuel ratio to a level that won't create a lot of pollutants.

The environment is more sensitive to exhaust pollutants than many people think, so your best bet is to replace a failed O2 sensor.

What repairs can fix code P0133?

• Usually oxygen sensor replacement clears code P0133.
• Sometimes the sensor itself will not trigger a code P0133, so a technician should check for other problems such as vacuum leaks, a dirty MAF sensor, or leaks in the exhaust system.

Additional comments to consider regarding code P0133

When diagnosing a code P0133, be sure to check for vacuum leaks, intake leaks, and also check the mass air flow sensor for oil buildup or other contaminants to avoid a misdiagnosis.

How to Fix P0133 Engine Code in 3 Minutes [2 DIY Methods / Only $8.35]

Need more help with your p0133 code?

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