P0145
Fix within 1-2 weeksYour engine's computer detected that the oxygen sensor after the catalytic converter on Bank 1 (Sensor 3) is responding too slowly to changes in the exhaust gas.
Code P0145 means your Bank 1 Sensor 3 O2 sensor is responding too slowly. Common causes: Faulty O2 sensor (80%), exhaust leak (10%), wiring issues (8%). Drivability: Yes, safe to drive. Repair cost: $50-$200 DIY, $150-$500 professional.
Can I Drive With P0145?
Yes, safe to drive
No restrictions
Stop driving immediately if: Flashing CEL, loud noises, burning smell, rotten egg smell, significant power loss
Symptoms of P0145
- 1Check Engine Light is on
- 2Slight decrease in fuel economy
- 3Vehicle may fail an emissions test
Common Causes of P0145
Parts most likely causing this code, ranked by probability
The O2 sensor itself has degraded and can no longer react quickly enough to changes in the exhaust stream.
80% of P0145 cases are fixed by replacing this part
An exhaust leak near the O2 sensor can allow outside air in, causing inaccurate and slow readings from the sensor.
10% of P0145 cases are fixed by repairing an exhaust leak
Damaged, corroded, or loose wiring to the O2 sensor can prevent it from sending accurate and timely signals to the engine computer.
8% of P0145 cases are fixed by repairing wiring or connectors
A rare internal fault in the engine computer can cause it to misinterpret or fail to process the O2 sensor's signal correctly.
2% of P0145 cases are fixed by replacing the ECM/PCM
Check These First (Before Buying Parts)
- Visually inspect the Bank 1 Sensor 3 O2 sensor's wiring and connector for any signs of damage, fraying, or corrosion. Ensure the connector is fully seated.
- Listen for any exhaust leaks near the O2 sensor. A small leak can cause the sensor to read incorrectly. Look for black soot marks on exhaust components.
How to Diagnose P0145
- 1Visually inspect the Bank 1 Sensor 3 oxygen sensor and its wiring for any obvious damage, corrosion, or loose connections.
- 2Check for any exhaust leaks near the Bank 1 Sensor 3 O2 sensor, listening for hissing sounds or looking for soot marks.
- 3Use an OBD-II scan tool to view live data for the Bank 1 Sensor 3 O2 sensor. Monitor its voltage fluctuations to see if it's responding slowly compared to specifications.
- 4If the sensor appears faulty after visual inspection and live data analysis, replace the Bank 1 Sensor 3 oxygen sensor.
- 5After replacing the sensor, clear the code and drive the vehicle to confirm the repair.
P0145 on Popular Vehicles
Honda Accord
2003-2024The Bank 1 Sensor 3 O2 sensor on Accords is typically a downstream sensor, often located in the exhaust pipe after the catalytic converter. Corrosion can make removal difficult. Using a quality O2 sensor socket is essential.
85% fixed by replacing the O2 sensor
Toyota Camry
2007-2024Camrys commonly experience O2 sensor failures as they age. The Bank 1 Sensor 3 is the downstream sensor. Check for exhaust leaks around the flex pipe or muffler connections, as these can mimic O2 sensor issues.
80% fixed by replacing the O2 sensor
Ford F-150
2004-2024On V8 F-150s, Bank 1 is the cylinder bank that contains cylinder #1. Sensor 3 is the downstream sensor for that bank. These sensors are exposed to road grime and salt, making wiring corrosion and sensor seizing common.
75% fixed by replacing the O2 sensor
Frequently Asked Questions
What does P0145 mean?
P0145 indicates that the oxygen sensor located after the catalytic converter on Bank 1 (Sensor 3) is not reacting quickly enough to changes in the exhaust gas composition. This sensor monitors the efficiency of your catalytic converter.
Can I drive with P0145?
Yes, you can drive safely with a P0145 code. This code primarily impacts your vehicle's emissions and fuel economy, not immediate drivability or engine damage. However, you should fix it within 1-2 weeks to prevent further issues.
Will P0145 clear itself?
No, P0145 will not clear itself. The engine computer stores this code until the underlying issue is resolved and the system monitors complete a successful drive cycle without detecting the fault. You will need to fix the problem and then clear the code with a scan tool.
How do I fix P0145 myself?
Start by inspecting the O2 sensor wiring and connector for damage or corrosion. Check for exhaust leaks near the sensor. If those are clear, the most common fix is replacing the Bank 1 Sensor 3 oxygen sensor. You'll need an O2 sensor socket for this.
How much does it cost to fix P0145?
A DIY fix for P0145 typically costs $50-$200 for a new oxygen sensor. If you take it to a shop, expect to pay $150-$500, which includes parts and labor.
P0145 keeps coming back - why?
If P0145 keeps returning, it means the root cause was not fully addressed. This often happens if you replaced the O2 sensor but missed an exhaust leak, a wiring issue, or if the new sensor itself was faulty. A thorough check of the exhaust system and wiring is necessary.
Will P0145 fail emissions/smog test?
Yes, P0145 will cause your vehicle to fail an emissions or smog test. The Check Engine Light being on is an automatic failure in most jurisdictions, and the slow O2 sensor response directly impacts the emissions monitoring system.
What's the difference between P0145 and P0140?
P0145 indicates the Bank 1 Sensor 3 O2 sensor is responding too slowly. P0140 means the same sensor is showing 'no activity detected,' implying it's completely dead or disconnected. P0145 is a partial failure, while P0140 is a complete failure of the sensor's signal.
P0145 on Honda Accord?
On many Honda Accords, the Bank 1 Sensor 3 O2 sensor is located after the catalytic converter, often under the vehicle. Access can sometimes be tight, requiring the right O2 sensor socket and possibly a breaker bar for removal. The sensor itself is a common wear item.
Questions to Ask Your Mechanic
Did you check for exhaust leaks near the Bank 1 Sensor 3 O2 sensor?
Good answer: Yes, I performed a visual inspection and listened for leaks. The exhaust system is sealed tight around that sensor.
What were the live data readings for the Bank 1 Sensor 3 O2 sensor?
Good answer: The sensor's voltage was fluctuating, but very slowly, taking over 1.5 seconds to switch from rich to lean, which is outside the acceptable range.
Repair Cost Estimate
DIY Repair
Parts only
$50-$200
Shop Repair
Parts + labor
$150-$500
Save $100-$300 by doing it yourself
Difficulty
intermediate
Time
1-2 hours
Intermediate - requires specific tools like an O2 sensor socket and an OBD-II scan tool to confirm the diagnosis and clear the code.
Cost of Waiting
Ignoring P0145 will cause your vehicle to fail emissions tests and can lead to reduced fuel economy. While it won't immediately damage your engine, a continuously slow O2 sensor can mask other issues or cause the engine computer to make incorrect fuel adjustments, potentially impacting catalytic converter longevity over a very long period. A $50-$200 sensor replacement now prevents ongoing fuel waste and emissions test failures.
While You're In There...
If you find an exhaust leak, replacing the relevant gasket (e.g., at a flange or flex pipe) is necessary to seal the system. It's often accessed when working on exhaust components.
Applying anti-seize to the threads of the new O2 sensor prevents it from seizing in the exhaust pipe, making future removal much easier. It's a cheap preventative measure.
Tools You'll Need
- OBD-II Scan Tool
- O2 Sensor Socket (7/8 inch or 22mm)
- Ratchet and Extension
- Wrench (for exhaust clamps if checking for leaks)
- Wire Brush (for cleaning threads)
- Anti-seize Compound
P0145 is a common emissions code. Most repairs involve replacing a worn-out oxygen sensor, which is a straightforward job for an intermediate DIYer. Your vehicle will run more efficiently and pass emissions tests once fixed.
- Family-owned since 1957
- 990,000+ happy customers
- Fast nationwide shipping
- Easy returns
Your Next Steps
Step 1: Inspect the O2 sensor wiring and connector for damage or corrosion. Also, check for any exhaust leaks near the sensor.
Step 2: If no obvious issues are found, use an OBD-II scan tool to monitor the live data from the Bank 1 Sensor 3 O2 sensor. Look for slow or erratic voltage readings.
Step 3: If the sensor's response is confirmed to be slow, replace the Bank 1 Sensor 3 oxygen sensor. Clear the code and perform a test drive.