Skip the auto shop - Our mechanics make house calls

P0145 OBD-II Trouble Code: O2 Sensor Circuit Slow Response (Bank 1, Sensor 3)

Check Engine Light

P0145 code definition

O2 Sensor Circuit Slow Response (Bank 1 Sensor 3)

What the P0145 code means

P0145 is the OBD-II generic code indicating that the O2 sensor for bank 1 sensor 3 fails to have a voltage drop to below .2 volts for 7 seconds during a deceleration fuel cut off. The Engine Control Module (ECM) has determined the sensor response to be too slow.

What causes the P0145 code?

  • The ECM cuts all fuel to the engine during deceleration and the O2 sensors all should respond with a voltage output below .2 volts showing the exhaust stream is higher in oxygen content with no fuel.

  • The code is set if the O2 sensor for bank 1 sensor 3 does not respond to the fuel cutoff for around 7 seconds.

  • The O2 sensor may be defective or the fuel system injector is leaking.

What are the symptoms of the P0145 code?

  • The engine may stall or run rough on deceleration; fuel is getting in the engine when the ECM has cut the fuel.

  • The Check Engine Light will come on once the ECM sees a problem with the O2 sensor.

  • The engine may hesitate upon acceleration after a deceleration phase if the engine is loaded up with fuel.

How does a mechanic diagnose the P0145 code?

  • Scans codes and documents freeze frame data for the O2 sensor

  • Monitors the O2 sensor data to see if the voltage is dropping to below .2 volts during deceleration for all the O2 sensors

  • Checks the fuel injection system for leaking injectors if all the O2 sensors indicate voltages above .2 volts on deceleration

  • Checks the engine fuel pressure for a leaking fuel injector or fuel pressure regulator

  • Checks the O2 sensor for contamination with coolant or oil

  • Checks the O2 sensor harness for water contamination

  • Follows the manufacturer's specific pinpoint tests for further diagnosis

Common mistakes when diagnosing the P0145 code?

Follow these simple guidelines to prevent mistakes:

  • Check the complete fuel system for other problems before replacing any O2 sensor.

  • Check the fuel injection system for any leaking injectors, or a pressure regulator that is causing fuel fouled O2 sensors and catalyst.

  • Repair oil or coolant leaks onto the O2 sensor before replacing the sensor to prevent contaminating the new sensor.

How serious is the P0145 code?

  • The ECM cannot control the fuel shut off if the fuel injectors are leaking. This will lead to excessive fuel consumption.

  • Excessive fuel in the exhaust stream on deceleration can cause the engine to stall or run rough.

  • A failed sensor will not affect the ECM’s control of the air-fuel ratio for the engine.

What repairs can fix the P0145 code?

Additional comments for consideration regarding the P0145 code

The slow response of an O2 sensor may be due to a sensor that is just getting old and over time may get contaminated with time with carbon and other contaminants that deteriorate the sensors ability to respond to the exhaust changes.

Need help with a P0145 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
Icon-warranty_badge-02

Skip the repair shop, our top-rated mechanics come to you.

At your home or office

Choose from 600+ repair, maintenance & diagnostic services. Our top-rated mechanics bring all parts & tools to your location.

Fair & transparent pricing

See labor & parts costs upfront, so you can book with confidence.

12-month, 12,000-mile warranty

Our services are backed by a 12-month, 12,000-mile warranty for your peace of mind.

Get A Quote

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.

GET A QUOTE

Post a question and get free advice from our certified mechanics.

ASK A QUESTION

More related articles

Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...
Veteran and Military Driver Laws and Benefits in New Mexico
The state of New Mexico offers a number of benefits and perks for those Americans who have either served in an Armed Forces branch...
How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...


Related questions

Q: P0328 code - 2008 Hyundai Accent

Hello. P0328 is the code for a knock sensor. If the knock sensor fails, or there is an issue with the wiring, the code may be set off. You also mention that the Check Engine Light was not on. If...

Q: P0700 Transmission Control System MIL Request

Hi! A P0700 code stored in the powertrain control module (PCM) indicates that there is a code stored in the transmission control module (TCM) that can be accessed by looking into the TCM with an appropriate scan tool. Having the...

Q: Truck hesitating and pulling to one side

It seems that your vehicle may be experiencing symptoms from multiple concerns: The pulling can possibly come from faulty suspension components, or a dragging brake caliper. Have a mechanic check the condition of the tires. This usually points to a...