OBD-II Trouble Codes

P0145 Code: O2 Sensor Circuit Slow Response (Bank 1 Sensor 3)

Reading Time: 3 minutes

Modern vehicles are equipped with on-board diagnostics (OBD) to make it easier for technicians to diagnose vehicle problems. While these codes are helpful to professionals, they may seem complicated at first to the average DIYer.

If you’re curious about what error code P0145 is, this informative guide is for you.

What Does the P0145 Code Mean?

Diagnostic trouble code (DTC) P0145 stands for “O2 Sensor Circuit Slow Response (Bank 1 Sensor 3).” It is logged when the powertrain control module (PCM) detects a slow response time from a downstream oxygen sensor.

“Bank 1” refers to the part of the engine containing cylinder 1. On the other hand, “sensor 3” pertains to the oxygen sensor located downstream or after the catalytic converter.

oxygen sensors that could be causing trouble code p0145
Code P0145 indicates that PCM detects a slow response time from a downstream oxygen sensor.

Oxygen sensors are designed to react to the changes in the composition of exhaust gases. This code is set if the sensor responds slower than usual to the changes in the exhaust.

Sensor 3 monitors the efficiency of the catalytic converters in reducing emissions and relays this data to the PCM. If the latter perceives a problem in the response time of this sensor, it sets trouble code P0145. The code is also set when the oxygen sensor is too slow to allow proper fuel control and closed-loop fuel system operation.

Note: The definition of code P0145 may be different depending on the vehicle manufacturer. Consult the appropriate repair manual or repair database for the exact code definition.

What are the Possible Causes of the P0145 Code?

P0145 is a generic code, so it can have several causes. Here are the most common:

exhaust leak
Code P0145 can be triggered by a leak in the engine exhaust.

What are the Common Symptoms of the P0145 Code?

You may notice the following symptoms if you own a vehicle with a logged P0145 trouble code:

How to Diagnose the P0145 Code

Error code P0145 is generic, which means it is supported by various makes and models. It may have triggers and symptoms similar to other DTCs. This can make its diagnosis and repair difficult for the average DIYer.

Vehicles are built differently depending on the manufacturer, so the exact diagnostic and repair procedures may vary. As a rule of thumb, always refer to a repair manual for the appropriate diagnostic steps.

If you’re not confident in your automotive knowledge, it might be best to leave the diagnosis to the experts instead of DIY-ing it.

poor fuel economy p0145
Poor fuel mileage is one of the common symptoms of code P0145.

How to Fix the P0145 Code

Code P0145 may be set in vehicles of varying makes and models. It may also share similar triggers and symptoms with other error codes. However, because cars are made differently, there is no single, fail-safe solution for this code. For instance, a solution that worked for a P0145 on a Chevy might not work for another model, especially if it’s from a different manufacturer.

All vehicles are different, so you should always refer to factory repair information that’s specific to your car before addressing the issue. If you aren’t confident in your automotive skills, it may be best to bring your vehicle to an auto repair shop for proper diagnosis and repair.

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