P0133
Fix within 1-2 weeksYour engine's upstream oxygen sensor (Bank 1 Sensor 1) is responding too slowly to changes in the exhaust gas.
Code P0133 means your upstream oxygen sensor (Bank 1 Sensor 1) is responding too slowly. Common causes: Faulty O2 sensor (80%), exhaust leak (10%). Drivability: Yes, safe to drive, but fix within 1-2 weeks. Repair cost: $50-$200 DIY, $150-$400 professional.
Can I Drive With P0133?
Yes, safe to drive
No restrictions, but fix within 1-2 weeks to prevent further issues and save on fuel.
Stop driving immediately if: Flashing CEL (indicates severe misfire), strong rotten egg smell (catalytic converter overheating), significant power loss, or engine running extremely rough.
Symptoms of P0133
- 1Check Engine Light is on
- 2Reduced fuel economy
- 3Engine may run rough or hesitate slightly
- 4Increased exhaust emissions
Common Causes of P0133
Parts most likely causing this code, ranked by probability
The upstream oxygen sensor wears out over time, becoming sluggish and unable to accurately report oxygen levels to the engine computer.
80% of P0133 cases are fixed by replacing this part
An exhaust leak before the upstream O2 sensor allows outside air to enter the exhaust stream, diluting the gases and causing the sensor to read incorrectly or respond slowly.
10% of P0133 cases are fixed by repairing an exhaust leak
Damaged, corroded, or loose wiring and connectors can prevent the O2 sensor's signal from reaching the engine computer correctly, leading to a slow response.
7% of P0133 cases are fixed by repairing wiring
Oil, coolant, or fuel additives can coat the sensor, reducing its ability to react quickly to changes in exhaust gas composition.
3% of P0133 cases are fixed by addressing sensor contamination
Check These First (Before Buying Parts)
- Visually inspect the Bank 1 Sensor 1 oxygen sensor and its wiring for any physical damage, fraying, or corrosion.
- Listen for any exhaust leaks near the engine or exhaust manifold. A small leak can often be heard as a ticking or hissing sound.
How to Diagnose P0133
- 1Visually inspect the Bank 1 Sensor 1 oxygen sensor and its wiring for any obvious damage, fraying, or corrosion.
- 2Check for any exhaust leaks upstream of the Bank 1 Sensor 1 oxygen sensor, listening for hissing sounds or looking for soot marks.
- 3Use an OBD-II scan tool to monitor the live data for the Bank 1 Sensor 1 oxygen sensor. Look for slow or flat voltage readings that do not fluctuate rapidly between 0.1V and 0.9V.
- 4Inspect the O2 sensor's heater circuit for proper resistance and voltage, as a faulty heater can cause slow sensor response.
- 5If all other checks are inconclusive, test the O2 sensor's internal resistance and signal output directly with a multimeter.
P0133 on Popular Vehicles
Toyota Camry
2007-2024P0133 is a common code on these models as the upstream O2 sensor ages. Replacement with a quality sensor is a direct fix.
85% fixed by O2 sensor replacement
Honda Accord
2003-2024Similar to Toyota, Honda Accords frequently trigger P0133 due to a worn-out primary (upstream) O2 sensor. Check for exhaust manifold cracks which can mimic a slow sensor.
80% fixed by O2 sensor replacement
Ford F-150
2004-2024On F-150s, especially with V8 engines, P0133 is often a failing upstream O2 sensor. Also, inspect the exhaust manifold for leaks, which are common on some Ford truck engines.
75% fixed by O2 sensor replacement
Frequently Asked Questions
What does P0133 mean?
P0133 indicates that the engine computer has detected a slow response time from the upstream oxygen sensor on Bank 1. This sensor is crucial for monitoring exhaust gases and adjusting fuel delivery.
Can I drive with P0133?
Yes, you can drive safely with a P0133 code, but you should fix it within 1-2 weeks. Your vehicle will likely experience reduced fuel economy and increased emissions, and prolonged driving can damage your catalytic converter.
Will P0133 clear itself?
No, P0133 will not clear itself. The underlying issue, typically a faulty oxygen sensor or an exhaust leak, needs to be repaired. The Check Engine Light will remain on until the problem is resolved and the code is cleared.
How do I fix P0133 myself?
Start by visually inspecting the O2 sensor and exhaust for leaks. If no issues are found, the most common fix is replacing the Bank 1 Sensor 1 oxygen sensor. Ensure the new sensor is correctly installed and the wiring is secure.
How much does it cost to fix P0133?
A DIY fix for P0133, primarily replacing the oxygen sensor, costs $50-$200 for the part and basic tools. Professional repair at a shop typically costs $150-$400, covering parts and labor.
P0133 keeps coming back - why?
If P0133 keeps returning, it often means the root cause was misdiagnosed. Double-check for subtle exhaust leaks, inspect the wiring and connector thoroughly, or ensure the replacement O2 sensor is a quality part and functioning correctly. Rarely, other engine issues causing rich/lean conditions can indirectly affect O2 sensor response.
Will P0133 fail emissions/smog test?
Yes, P0133 will cause your vehicle to fail an emissions or smog test. The Check Engine Light being on automatically fails the test, and the slow O2 sensor response directly impacts the vehicle's ability to control emissions effectively.
What's the difference between P0133 and P0134?
P0133 indicates the Bank 1 Sensor 1 oxygen sensor is responding too slowly. P0134 indicates the same sensor has 'no activity detected,' meaning it's completely dead or disconnected. P0133 is a sluggish sensor, while P0134 is a non-functional sensor.
P0133 on Toyota Camry
On many Toyota Camry models, P0133 is a common code around 100,000-150,000 miles due to the natural wear of the upstream oxygen sensor. Replacing the Denso brand sensor (which is often OEM) usually resolves the issue.
Questions to Ask Your Mechanic
Did you check the live data for the Bank 1 Sensor 1 oxygen sensor to confirm its response time?
Good answer: Yes, I monitored the sensor's voltage fluctuations on the scan tool. It was clearly sluggish, not switching rapidly enough.
Did you inspect for any exhaust leaks before the upstream O2 sensor?
Good answer: Yes, I performed a visual and audible inspection for leaks around the manifold and exhaust pipe before the sensor. There were no signs of leaks.
Repair Cost Estimate
DIY Repair
Parts only
$50-$200
Shop Repair
Parts + labor
$150-$400
Save $100-$200 by doing it yourself
Difficulty
intermediate
Time
0.5-1.5 hours
Intermediate - requires an OBD-II scan tool to confirm diagnosis and an oxygen sensor socket for removal/installation, which can sometimes be challenging due to rust.
Cost of Waiting
Ignoring P0133 leads to your engine running inefficiently, burning more fuel, and increasing harmful emissions. Over time, the incorrect fuel mixture can cause premature failure of your catalytic converter, turning a $50-$200 sensor replacement into a $800-$2,500 catalytic converter job.
While You're In There...
If you find an exhaust leak or are removing exhaust components to access the sensor, replacing old gaskets prevents future leaks and ensures a tight seal.
Applying anti-seize to the threads of the new O2 sensor prevents it from seizing in the exhaust pipe, making future removal much easier.
Tools You'll Need
- OBD-II scan tool
- Oxygen sensor socket (7/8 inch or 22mm)
- Ratchet and extensions
- Wrench set
- Anti-seize compound
- Safety glasses
- Gloves
P0133 is a very common code, often indicating a simple sensor replacement. Most repairs are straightforward, and your vehicle's fuel economy and performance will improve significantly afterward.
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Your Next Steps
Step 1: Visually inspect the Bank 1 Sensor 1 oxygen sensor and its wiring for any damage or corrosion. Also, check for any exhaust leaks before the sensor.
Step 2: If no obvious issues are found, use an OBD-II scan tool to monitor the live data for the Bank 1 Sensor 1 O2 sensor. Look for slow or flat voltage readings.
Step 3: If the sensor's response is slow, the most likely fix is replacing the Bank 1 Sensor 1 oxygen sensor. You'll likely need a new O2 sensor and an O2 sensor socket.