AutoCodes – Suzuki – P0138 Suzuki

P0138 Suzuki Code - HO2S Circuit High Voltage Bank 1 Sensor 2

Quick Answer

The Heated Oxygen Sensors (HO2S) are used for fuel control and catalyst monitoring. Common causes include Faulty Heated Oxygen Sensors (HO2S) Bank 1 Sensor 2, Heated Oxygen Sensors Bank 1 Sensor 2 harness is open or shorted, Heated Oxygen Sensors 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: P0138 Suzuki indicates HO2S Circuit High Voltage Bank 1 Sensor 2.
Common causes: Common causes include Faulty Heated Oxygen Sensors (HO2S) Bank 1 Sensor 2, Heated Oxygen Sensors Bank 1 Sensor 2 harness is open or shorted, Heated Oxygen Sensors 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 4,964

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Nov 24, 2020

Description
Step-by-Step Diagnostic Guide
Possible Causes
How To Fix
Cost to Diagnose
FAQs
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Code P0138 Suzuki 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 control module operates in an Open Loop mode, ignoring the HO2S signal voltage while calculating the air-to-fuel ratio. The control module supplies the HO2S with a reference or bias voltage of about 450 mV. While the engine runs, the HO2S heats up and begins to generate a voltage within a range of 0-1,000 mV. This voltage will fluctuate above and below the bias voltage. Once sufficient HO2S voltage fluctuation is observed by the control module, Closed Loop is entered. The control module uses the HO2S voltage to determine the air-to-fuel ratio. An HO2S voltage that increases above bias voltage toward 1,000 mV indicates a rich fuel mixture. An HO2S voltage that decreases below bias voltage 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 control module to calculate the air-to-fuel ratio sooner.
The Diagnostic Trouble Code (DTC) will set if the Engine Control Module (ECM) detects that a secondary HO2S signal voltage is more or less than 60 mV for greater than 4 seconds of for a cumulative of 50 seconds.

OBDII Code P0138 Suzuki - HO2S Circuit High Voltage Bank 1 Sensor 2 - AutoCodes.com — P0138 Suzuki Code - HO2S Circuit High Voltage Bank 1 Sensor 2

What does this mean?

What are the Possible Causes of the DTC P0138 Suzuki?

Faulty Heated Oxygen Sensors (HO2S) Bank 1 Sensor 2
Heated Oxygen Sensors Bank 1 Sensor 2 harness is open or shorted
Heated Oxygen Sensors Bank 1 Sensor 2 circuit poor electrical connection
Faulty Engine Control Module (ECM)

How to Fix the DTC P0138 Suzuki?

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 P0138 Suzuki 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.

Frequently Asked Questions about P0138 Suzuki Code

1. What are the common symptoms of OBDII code P0138 (HO2S Circuit High Voltage Bank 1 Sensor 2) in a Suzuki?

- Common symptoms include poor fuel economy, rough idling, engine misfires, and the illumination of the Check Engine Light.

2. What does the OBDII code P0138 indicate in a Suzuki vehicle?

- This code indicates that the oxygen sensor (Bank 1 Sensor 2) is reporting a voltage higher than the normal operating range.

3. What are the possible causes of the P0138 code in a Suzuki?

- The potential causes include a faulty oxygen sensor, wiring issues in the oxygen sensor circuit, exhaust leaks, engine misfires, or a malfunctioning engine control module (ECM).

4. How can I diagnose the P0138 code in my Suzuki?

- Diagnosis typically involves using an OBDII scanner to read the code, inspecting the oxygen sensor and related wiring for damage, checking for exhaust leaks, and testing the sensor's voltage output.

5. Can I drive my Suzuki with the P0138 code?

- It is not recommended to drive with the P0138 code, as it can lead to poor engine performance and potentially cause damage to the catalytic converter if left unresolved.

6. How can I repair the P0138 code in my Suzuki?

- Repair options may include replacing the oxygen sensor, repairing or replacing damaged wiring, fixing exhaust leaks, addressing misfires, or reprogramming the ECM.

7. Is it possible to reset the P0138 code in a Suzuki without fixing the underlying issue?

- While you can clear the code with an OBDII scanner, it is crucial to address the root cause to prevent the code from reoccurring and to ensure proper vehicle operation.

8. How much does it typically cost to repair the P0138 code in a Suzuki?

- The cost of repairs for the P0138 code can vary depending on the specific issue, but it may range from $100 to $300 for parts and labor.

9. Can a DIY enthusiast fix the P0138 code in a Suzuki at home?

- Depending on your skill level and access to tools, you may be able to replace the oxygen sensor or address minor wiring issues at home. However, more complex repairs may require professional assistance.

10. How often does the P0138 code occur in Suzuki vehicles?

- The P0138 code can occur sporadically in Suzuki vehicles, especially in older models or those with high mileage, due to normal wear and tear on the oxygen sensor and related components.