AutoCodes – GMC – P0137 GMC

P0137 GMC Code - HO2S Circuit Low Voltage Bank 1 Sensor 2

Quick Answer

The Heated Oxygen Sensors (HO2S) are used for fuel control and catalyst monitoring. Common causes include Faulty Rear Heated Oxygen Sensor Bank 1, Rear Heated Oxygen Sensor Bank 1 harness is open or shorted, Rear Heated Oxygen Sensor Bank 1 circuit poor electrical connection. Severity is Moderate - service should be scheduled soon. The vehicle may still be drivable for short trips if it runs normally, but avoid hard driving and repair it soon.

What it means: P0137 GMC indicates HO2S Circuit Low Voltage Bank 1 Sensor 2.
Common causes: Common causes include Faulty Rear Heated Oxygen Sensor Bank 1, Rear Heated Oxygen Sensor Bank 1 harness is open or shorted, Rear Heated Oxygen Sensor Bank 1 circuit poor electrical connection.
Severity: Moderate - service should be scheduled soon.
Can I drive?: The vehicle may still be drivable for short trips if it runs normally, but avoid hard driving and repair it soon.

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Code Popularity 20,916

How popular is this code, among other codes? Low

Repair Importance Level

Moderate (Service soon) (2 / 3)

Repair Difficulty Level

Intermediate (2 / 3)

What is this?

Table of contents Created and updated by William Orellana on May 26, 2022

Description
Step-by-Step Diagnostic Guide
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code P0137 GMC Description

The Heated Oxygen Sensors (HO2S) are used for fuel control and catalyst monitoring. Each HO2S compares the oxygen content of the surrounding air with the oxygen content of the exhaust stream. When the engine is started, the Engine Control Module (ECM) operates in an Open Loop mode, ignoring the HO2S signal voltage while calculating the air-to-fuel ratio. While the engine runs, the HO2S heats up and begins to generate a voltage within a range of 0 - 1, 000 mV. Once sufficient HO2S voltage fluctuation is observed by the ECM, Closed Loop is entered. The ECM uses the HO2S voltage to determine the air-to-fuel ratio. An HO2S voltage that increases toward 1, 000 mV indicates a rich fuel mixture. An HO2S voltage that decreases toward 0 mV indicates a lean fuel mixture.
The heating elements inside each HO2S heat the sensor to bring the sensor up to operating conditions faster. This allows the system to enter Closed Loop earlier and the ECM to calculate the air-to-fuel ratio sooner.
The Diagnostic Trouble Code (DTC) will be set when the ECM detects that the heated oxygen sensor is shorted to ground if the HO2S voltage is less than 50 mV.

OBDII Code P0137 GMC - HO2S Circuit Low Voltage Bank 1 Sensor 2 - AutoCodes.com — P0137 GMC Code - HO2S Circuit Low Voltage Bank 1 Sensor 2

What does this mean?

What are the Possible Causes of the DTC P0137 GMC?

Faulty Rear Heated Oxygen Sensor Bank 1
Rear Heated Oxygen Sensor Bank 1 harness is open or shorted
Rear Heated Oxygen Sensor Bank 1 circuit poor electrical connection
Low or high fuel system pressure
Fuel contamination
Faulty fuel injectors
Exhaust gas leaks
Engine vacuum leaks

How to Fix the DTC P0137 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 does this mean?

Code Tech Notes

Replacing the Rear Heated Oxygen Sensor (HO2S) Bank 1 usually takes care of the problem.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0137 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.

Need more information about the P0137 GMC code?

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Information for Specific GMC Models

P0137 2014 GMC Sierra — HO2S Circuit Low Voltage Bank 1 Sensor 2
P0137 2015 GMC Sierra — HO2S Circuit Low Voltage Bank 1 Sensor 2
P0137 2016 GMC Sierra — HO2S Circuit Low Voltage Bank 1 Sensor 2
P0137 2017 GMC Sierra — HO2S Circuit Low Voltage Bank 1 Sensor 2
P0137 2018 GMC Sierra — HO2S Circuit Low Voltage Bank 1 Sensor 2

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.

Frequently Asked Questions about P0137 GMC Code

What does the OBDII code P0137 mean on a GMC vehicle?

P0137 indicates that the oxygen sensor (HO2S) in Bank 1, Sensor 2, is detecting a consistently low voltage, which suggests an issue with the sensor or the fuel mixture.

What are the symptoms of code P0137 on a GMC?

Symptoms may include the Check Engine Light turning on, reduced fuel efficiency, rough idling, hesitation during acceleration, or a failed emissions test.

What causes the P0137 code to appear on a GMC?

Common causes include a faulty oxygen sensor, damaged wiring or connectors, a vacuum leak, a clogged catalytic converter, or an exhaust leak.

How do I locate Bank 1, Sensor 2 on my GMC?

Bank 1 refers to the side of the engine with cylinder 1, and Sensor 2 is the downstream oxygen sensor located after the catalytic converter.

Can I drive my GMC with the P0137 code active?

While it may be possible to drive with this code active, it is not recommended as it can lead to poor fuel economy, increased emissions, and potential damage to the catalytic converter.

How can I fix the P0137 code on my GMC?

Repairs may include replacing the faulty oxygen sensor, repairing damaged wiring or connectors, fixing exhaust or vacuum leaks, or replacing a clogged catalytic converter.

How can I test the oxygen sensor for P0137 on a GMC?

You can use a multimeter or scan tool to check the voltage readings of the downstream oxygen sensor. A consistent voltage below 0.1 volts suggests a problem.

Is the P0137 code related to the engineâ€™s fuel mixture?

Yes, the code often indicates that the engine is running too lean (not enough fuel) or there is an issue with the oxygen sensorâ€™s ability to measure the air-fuel mixture accurately.

How much does it cost to repair the P0137 code on a GMC?

Repair costs vary, but replacing an oxygen sensor typically costs between $150 and $300, including parts and labor. Additional repairs for wiring or leaks may increase the cost.

Can a bad catalytic converter trigger the P0137 code on a GMC?

Yes, a clogged or failing catalytic converter can cause low oxygen sensor voltage readings and trigger the P0137 code.