AutoCodes – GMC – P0038 GMC

P0038 GMC Code - HO2S Heater Control Circuit High Voltage Bank 1 Sensor 2

Quick Answer

Heated Oxygen Sensors (HO2S) are used for fuel control and post catalyst monitoring. Common causes include Faulty Heated Oxygen Sensor (H2OS) Bank 1 Sensor 2, Heated Oxygen Sensor Bank 1 Sensor 2 harness is open shorted to ground, Heated Oxygen Sensor Bank 1 Sensor 2 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: P0038 GMC indicates HO2S Heater Control Circuit High Voltage Bank 1 Sensor 2.
Common causes: Common causes include Faulty Heated Oxygen Sensor (H2OS) Bank 1 Sensor 2, Heated Oxygen Sensor Bank 1 Sensor 2 harness is open shorted to ground, Heated Oxygen Sensor Bank 1 Sensor 2 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 4,865

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 Mar 23, 2024

Description
Step-by-Step Diagnostic Guide
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code P0038 GMC Description

Heated Oxygen Sensors (HO2S) are used for fuel control and post catalyst monitoring. Each HO2S compares the oxygen content of the surrounding air with the oxygen content in the exhaust stream. The HO2S must reach an operating temperature to provide an accurate voltage signal. A heating element inside the HO2S minimizes the time required for the sensors to reach operating temperature. Voltage is provided to the heater by an ignition voltage circuit through a fuse. With the engine running, the ground is provided to the heater by the HO2S heater low control circuit through a low side driver within the Engine Control Module (ECM). The ECM uses Pulse Width Modulation (PWM) to control the HO2S heater operation to maintain a specific HO2S operating temperature range.
The Diagnostic Trouble Code (DTC) will be set when the ECM detects a short to voltage in the heater output low side driver circuit of the heated oxygen sensor when the heater is commanded ON for greater than 5 s.

OBDII Code P0038 GMC - HO2S Heater Control Circuit High Voltage Bank 1 Sensor 2 - AutoCodes.com — P0038 GMC Code - HO2S Heater Control Circuit High Voltage Bank 1 Sensor 2

What does this mean?

What are the Possible Causes of the DTC P0038 GMC?

Faulty Heated Oxygen Sensor (H2OS) Bank 1 Sensor 2
Heated Oxygen Sensor Bank 1 Sensor 2 harness is open shorted to ground
Heated Oxygen Sensor Bank 1 Sensor 2 circuit poor electrical connection
Heated Oxygen Sensor Bank 1 Sensor 2 circuit fuse
Faulty Engine Control Module (ECM)

How to Fix the DTC P0038 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

The code means that there is a problem with the heater element circuit of the heated oxygen sensor. The control module monitors how long it takes the sensor to warm up and start sending an adequate signal. The code is set when the sensor is taking too long to warm up. Water getting inside the heated oxygen sensor connector can cause the heated oxygen sensor fuse to blow. Before replacing the sensor, check for the condition of the heated oxygen sensor fuse and connectors. If the fuse and connector are OK, replacing the O2 Sensor usually takes care of the problem.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0038 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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Information for Specific GMC Models

P0038 2014 GMC Sierra — HO2S Heater Control Circuit High Voltage Bank 1 Sensor 2
P0038 2015 GMC Sierra — HO2S Heater Control Circuit High Voltage Bank 1 Sensor 2
P0038 2016 GMC Sierra — HO2S Heater Control Circuit High Voltage Bank 1 Sensor 2
P0038 2017 GMC Sierra — HO2S Heater Control Circuit High Voltage Bank 1 Sensor 2
P0038 2018 GMC Sierra — HO2S Heater Control Circuit High 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 P0038 GMC Code

What does the OBDII code P0038 mean on a GMC?

P0038 indicates a high voltage issue in the heater control circuit for the oxygen sensor (HO2S) located on Bank 1, Sensor 2.

What are the common symptoms of P0038 in a GMC?

Symptoms may include an illuminated check engine light, decreased fuel efficiency, and difficulty passing emissions tests.

What causes the P0038 code on a GMC vehicle?

Common causes include a faulty oxygen sensor, damaged wiring or connectors in the heater circuit, a blown fuse, or a malfunctioning powertrain control module (PCM).

Can I drive my GMC with a P0038 code?

While the vehicle may still be drivable, ignoring this code can lead to reduced fuel efficiency and possible damage to the catalytic converter over time.

How do I fix the P0038 code on my GMC?

Repairs may include replacing the oxygen sensor, repairing damaged wiring or connectors, checking and replacing fuses, or updating/replacing the PCM if necessary.

How can I test the oxygen sensor heater circuit for P0038?

Use a multimeter to check for proper voltage and resistance in the heater circuit wiring and across the oxygen sensor's heater element.

Does P0038 always mean the oxygen sensor needs replacing?

No, the issue could also stem from wiring problems, a faulty fuse, or ECM/PCM issues, so proper diagnosis is essential.

Where is Bank 1, Sensor 2 located on a GMC?

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

What tools are needed to diagnose and fix P0038?

You’ll need an OBDII scanner, a multimeter, and possibly basic hand tools like wrenches and screwdrivers for sensor replacement or wiring repair.

How much does it cost to repair a P0038 code on a GMC?

The cost varies but typically ranges from $150 to $300 if replacing the oxygen sensor. Wiring repairs or PCM issues may cost more, depending on the extent of the damage.