When your vehicle’s onboard diagnostic system detects an irregularity with the oxygen sensor, it triggers the OBD2 code P0133. This code indicates that the oxygen sensor circuit is responding slower than expected, which can impact engine performance and emissions.
What Does the P0133 Code Mean?
The OBD-II Code P0133 is defined as an Oxygen Sensor Circuit Slow Response (Bank 1, Sensor 1). This code is triggered when the powertrain control module (PCM) determines that the oxygen sensor voltage switch from below 400 millivolts to above 450 millivolts is taking too long, exceeding the threshold of less than 100 milliseconds.
What Causes the P0133 Code?
Several factors can trigger the P0133 code, including:
- Defective oxygen sensor or air fuel ratio sensor
- Issues with the oxygen sensor heater circuit
- Exhaust system leaks
- Intake air system leaks
- Low fuel pressure
- Defective engine coolant temperature sensor
- Wiring or circuit problems related to the sensor
- Outdated PCM software
- Faulty PCM
What Are the Symptoms of the P0133 Code?
Common symptoms of a P0133 code include:
- Check Engine Light illuminated
- Vehicle may idle or run rough
- Decrease in fuel economy
- Engine may die unexpectedly
- Black smoke from the exhaust
- Unpleasant exhaust odors
- In some cases, there may be no noticeable symptoms
How Serious Is the P0133 Code?
The P0133 code is classified as a moderate severity issue. While it may not pose an immediate threat to vehicle safety or functionality, it is advisable to diagnose and address the problem within a reasonable timeframe to maintain optimal vehicle performance and emissions control.
How to Diagnose the P0133 Code
Diagnosing the P0133 code involves several steps:
- Record freeze frame data when the code is triggered.
- Reproduce the driving conditions that caused the code to set, using a data streaming scan tool.
- Inspect the oxygen sensor and connections, verifying power and ground signals.
- Check the signal from the oxygen sensor to the PCM using a Digital Volt Ohm Meter (DVOM).
- Perform a visual inspection of the exhaust system for leaks and the sensor harness for damage.
Common Repairs for the P0133 Code
Common repairs to address the P0133 code include:
- Replacing the defective oxygen sensor
- Repairing or replacing faulty wiring or connections
- Fixing exhaust or intake leaks
- Updating PCM software
- Replacing the PCM if found defective
How Much Does It Cost to Fix the P0133 Code?
The cost to fix the P0133 code can vary widely depending on the underlying issue. Typical expenses may range from $100 to $400 or more, depending on whether a simple sensor replacement is needed or if more extensive repairs are required.
Can I Fix the P0133 Code Myself?
While some aspects of diagnosing and repairing the P0133 code can be done by a knowledgeable DIY mechanic, it is recommended to have access to specialized diagnostic tools and equipment. If you’re not comfortable with vehicle diagnostics or repairs, seeking help from a certified technician is advisable.
