AutoCodes – Cadillac – P0038 Cadillac

P0038 Cadillac 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 Cadillac 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 5,447

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

What does this mean?

What are the Possible Causes of the DTC P0038 Cadillac?

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 Cadillac?

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 Cadillac 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 P0038 Cadillac Code

1. What are the common symptoms of OBDII code P0038 in a Cadillac?

The common symptoms of OBDII code P0038 in a Cadillac include poor fuel economy, rough idling, stalling, and the illumination of the Check Engine light.

2. What does the OBDII code P0038 "HO2S Heater Control Circuit High Voltage Bank 1 Sensor 2" mean?

This code indicates that there is a high voltage condition detected in the heating element circuit of the downstream oxygen sensor (Sensor 2) in Bank 1 of the engine.

3. What are the possible causes of OBDII code P0038 in a Cadillac?

Possible causes of OBDII code P0038 in a Cadillac include a faulty oxygen sensor, damaged wiring or connectors, a blown fuse, or a malfunctioning PCM (Powertrain Control Module).

4. How can I diagnose and repair OBDII code P0038 in my Cadillac?

To diagnose and repair OBDII code P0038, you can start by checking the oxygen sensor wiring and connectors for any damage. You may need to test the sensor and its heater circuit for proper operation. If necessary, replace the oxygen sensor or repair any damaged wiring.

5. Can I continue to drive my Cadillac with OBDII code P0038?

It is generally not recommended to continue driving your Cadillac with OBDII code P0038, as it can lead to reduced fuel efficiency and potential damage to the catalytic converter over time. It is best to address the issue promptly.

6. How much does it typically cost to repair OBDII code P0038 in a Cadillac?

The cost of repairing OBDII code P0038 in a Cadillac can vary depending on the specific issue causing the code. Generally, the cost can range from $100 to $300 for parts and labor.

7. Is OBDII code P0038 a serious problem in a Cadillac?

While OBDII code P0038 may not cause immediate drivability issues, it should be addressed promptly to prevent further damage to the vehicle and ensure optimal engine performance and fuel efficiency.

8. Can a DIY enthusiast fix OBDII code P0038 in a Cadillac?

Depending on your level of automotive knowledge and skills, a DIY enthusiast may be able to diagnose and repair OBDII code P0038 in a Cadillac. However, if you are unsure or inexperienced, it is recommended to seek professional help.

9. Will resetting the Check Engine light resolve OBDII code P0038 in a Cadillac?

Simply resetting the Check Engine light will not fix the underlying issue causing OBDII code P0038 in a Cadillac. It is important to diagnose the problem and address it properly to prevent the code from reoccurring.

10. How often does OBDII code P0038 occur in Cadillacs?

OBDII code P0038, indicating a high voltage condition in the oxygen sensor heater circuit, can occur in Cadillacs due to various reasons such as sensor failure or wiring issues. It is not extremely common but can occur in older vehicles or those with high mileage.