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1999 Dodge Durango 5.2L Engine P0138 O2 Sensor Issue - What Does It Mean and How to Fix?

Model: 1999 Durango Fault Code: P0138 Posted: 2008-05-28 14:04

I own a 1999 Dodge Durango with a 5.2L V8 engine and 145,000 miles on the odometer. The Check Engine Light (CEL) came on, so I took it to an auto shop which diagnosed code P0138 — Bank 1 Sensor 2 O2 sensor malfunction. I initially thought a simple O2 sensor replacement would fix it, but I had to wait until payday to act. I filled the tank the next day and drove approximately 50 miles; after that, the CEL turned off and has not come back on since. I'm now wondering if my fuel efficiency is compromised. The truck's onboard computer shows 12.9 MPG, which seems lower than when my wife used to drive it — I recall getting over 14 MPG back then. Given this history, what should I expect in terms of real-world fuel economy for a vehicle with P0138? Is the issue affecting mileage or just a temporary glitch?

Related fault codes

P0138

Comments (3)

Anonymous 2008-05-29 05:06

P0138 typically indicates an aging or failing O2 sensor, especially in bank 1. Replacing it with high-quality sensors can significantly improve fuel efficiency and engine performance. It's recommended to replace the sensor as soon as possible to avoid further issues.

Anonymous 2008-05-29 08:13

It's generally advised to replace all O2 sensors at once for optimal performance, especially in older vehicles like the 1999 Durango. How many O2 sensors does a 5.2L 1999 Dodge Durango have? The Check Engine Light has been on for over two weeks now, but fuel economy remains steady at 12.9 MPG — is this normal or could there be another underlying issue?

Anonymous 2008-05-29 18:37

I don't know the exact configuration without inspecting the vehicle, but most 5.2L Durangos have at least two O2 sensors in the exhaust system. For a definitive answer, you can crawl under the truck to check or provide the VIN to your dealer for diagnostic support.