AutoCodes – GMC – P1139 GMC

P1139 GMC Code - HO2S Insufficient Switching Bank 1 Sensor 2

Quick Answer

P1139 GMC indicates HO2S Insufficient Switching Bank 1 Sensor 2. Common causes include Faulty HO2S Bank 1 Sensor 2, HO2S Bank 1 Sensor 2 harness is open or shorted, HO2S Bank 1 Sensor 2 circuit poor electrical connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means: P1139 GMC indicates HO2S Insufficient Switching Bank 1 Sensor 2.
Common causes: Common causes include Faulty HO2S Bank 1 Sensor 2, HO2S Bank 1 Sensor 2 harness is open or shorted, HO2S Bank 1 Sensor 2 circuit poor electrical connection.
Severity: High - diagnose this code as soon as possible.
Can I drive?: Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

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Code Popularity 3,443

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Intermediate (2 / 3)

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Table of contents Created and updated by William Orellana on Apr 30, 2019

Description
Possible Causes
How To Fix
Cost to Diagnose
Comments
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Code P1139 GMC Description

OBDII Code P1139 GMC - HO2S Insufficient Switching Bank 1 Sensor 2 - AutoCodes.com — P1139 GMC Code - HO2S Insufficient Switching Bank 1 Sensor 2

What does this mean?

What are the Possible Causes of the DTC P1139 GMC?

Faulty HO2S Bank 1 Sensor 2
HO2S Bank 1 Sensor 2 harness is open or shorted
HO2S Bank 1 Sensor 2 circuit poor electrical connection

How to Fix the DTC P1139 GMC?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P1139 GMC code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.