P0133 - O2 Sensor Circuit Slow Response Bank 1 Sensor 1
P0133 is a generic powertrain diagnostic trouble code indicating O2 Sensor Circuit Slow Response Bank 1 Sensor 1. It relates to the Fuel & Air Metering system.
DTC Breakdown (SAE J2012)
| System | Powertrain (P) |
| Type | Generic |
| Subsystem | Fuel & Air Metering |
| Fault Index | 33 |
| Standard | SAE J2012 / ISO 15031-6 |
What does diagnostic code P0133 mean?
The oxygen sensor for Bank 1 Sensor 1 has a slow response time, meaning the sensor takes too long to switch between high (rich) and low (lean) voltage readings.
Severity Level & Driveability Details
Severity: Moderate
A sluggish sensor delays fuel trim adjustments, resulting in poor emissions and slightly lower fuel economy.
Common Symptoms of P0133
- Malfunction indicator lamp (MIL) turns on due to slow O2 sensor response.
- Minor drop in fuel mileage.
- Occasional engine stumble.
Typical Causes for P0133
- Aged or contaminated upstream O2 sensor (silicone, soot, coolant).
- Exhaust leaks upstream of O2 sensor.
- Dirty maf-sensor/">mass air flow sensor.
Diagnostic and Troubleshooting Steps
Graph O2 sensor voltage on an oscilloscope or scan tool. It should switch from high to low at least several times per second. If the waveform is rounded and slow, the sensor is fouled or worn out.
Typical Repairs and Fixes
- Replacing the Bank 1 Sensor 1 oxygen sensor to resolve slow switching response.
- Cleaning the MAF sensor to restore O2 response rate.
- Repairing upstream exhaust leaks.
Sensor Location & Parts Involved
The oxygen sensor is located in the exhaust pipe, either upstream (Sensor 1) or downstream (Sensor 2) of the catalytic converter.
Clearing Code & Recurrence
Clear the code using an OBD2 scanner and perform a drive cycle to reset the monitors.
Emissions & Smog Inspection Impact
Can cause rich running (excess carbon monoxide and hydrocarbons) or lean running (excess nitrogen oxides).
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Related Diagnostic Codes
Sources & References
This diagnostic guide is compiled and verified against the following authority sources:
- EPA Emissions OBD Guide
- SAE J2012 specifications
Frequently Asked Questions about P0133
What does the Bank 1 Sensor 1 O2 sensor slow response code P0133 mean?
The engine control module logged P0133 because it detected a slow response in the oxygen (O2) sensor circuit for Bank 1, Sensor 1.
Is it safe to drive with the Bank 1 Sensor 1 O2 sensor slow response code P0133 active?
Yes, but engine fuel efficiency will decrease until the sensor is replaced.
How much does it cost to repair a Bank 1 Sensor 1 O2 sensor slow response code P0133 fault?
Replacement parts cost $80-$200. Labor to replace the sensor is $70-$150 depending on rust and access.
What are the common causes of the Bank 1 Sensor 1 O2 sensor slow response code P0133?
Trigger conditions for the Bank 1 Sensor 1 O2 sensor slow response code P0133 include: Failed oxygen sensor (Sensor 1 on Bank 1)., Corroded wiring or loose electrical connector at the sensor plug., Blown O2 sensor circuit fuse..
Can I clear the check engine light for Bank 1 Sensor 1 O2 sensor slow response code P0133?
Clear the code using an OBD2 scanner and perform a drive cycle to reset the monitors.
Will the Bank 1 Sensor 1 O2 sensor slow response code P0133 cause an inspection failure?
Can cause rich running (excess carbon monoxide and hydrocarbons) or lean running (excess nitrogen oxides).