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Engine-Codes – GMC – P242D GMC

P242D GMC Code - Exhaust Gas Temperature Sensor 3 Circuit High Voltage

Quick Answer

The P242D diagnostic trouble code (DTC) for GMC vehicles refers to a problem with the Exhaust Gas Temperature (EGT) Sensor 3 Circuit registering high voltage. Common causes include Faulty EGT Sensor: The sensor itself may be malfunctioning, leading to incorrect voltage readings, Wiring Issues: Damaged or corroded wiring connections to the EGT sensor can cause high voltage readings, Exhaust System Leaks: Leaks in the exhaust system can affect the EGT sensor's readings, triggering the P242D code. 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
P242D GMC indicates Exhaust Gas Temperature Sensor 3 Circuit High Voltage.
Common causes
Common causes include Faulty EGT Sensor: The sensor itself may be malfunctioning, leading to incorrect voltage readings, Wiring Issues: Damaged or corroded wiring connections to the EGT sensor can cause high voltage readings, Exhaust System Leaks: Leaks in the exhaust system can affect the EGT sensor's readings, triggering the P242D code.
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.
What is this?
Table of contents Created and updated by William Orellana on Aug 30, 2024
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Code P242D GMC Description

The P242D diagnostic trouble code (DTC) for GMC vehicles refers to a problem with the Exhaust Gas Temperature (EGT) Sensor 3 Circuit registering high voltage. This sensor is responsible for monitoring the temperature of exhaust gases leaving the engine. When the EGT Sensor 3 Circuit detects a voltage higher than the specified range, it triggers the P242D code. This issue can lead to incorrect readings being sent to the engine control module, potentially impacting fuel delivery, emissions control, and overall engine performance.

OBDII Code P242D GMC - Exhaust Gas Temperature Sensor 3 Circuit High Voltage
P242D GMC Code - Exhaust Gas Temperature Sensor 3 Circuit High Voltage

Common Causes of P242D GMC

  1. Faulty EGT Sensor: The sensor itself may be malfunctioning, leading to incorrect voltage readings.
  2. Wiring Issues: Damaged or corroded wiring connections to the EGT sensor can cause high voltage readings.
  3. Exhaust System Leaks: Leaks in the exhaust system can affect the EGT sensor's readings, triggering the P242D code.
  4. Engine Tuning: Aftermarket engine modifications or tuning that impact exhaust gas temperatures can trigger this code.
  5. Engine Control Module (ECM) Malfunction: A malfunctioning ECM may not interpret the sensor readings correctly, leading to the code being set.

Symptoms of P242D GMC

  1. Check Engine Light: The most common symptom associated with this code is the illumination of the check engine light on the vehicle's dashboard.
  2. Reduced Engine Power: The vehicle may go into a reduced power mode to prevent damage due to incorrect temperature readings.
  3. Decreased Fuel Efficiency: Incorrect EGT sensor readings can lead to inefficient fuel delivery, resulting in decreased fuel economy.
  4. Rough Idle: The engine may experience rough idling or hesitation during acceleration.
  5. Increased Emissions: High exhaust gas temperatures can lead to increased emissions output, potentially causing the vehicle to fail emissions tests.

How to Fix P242D GMC

  1. Diagnose: Use a diagnostic scanner to read the code and verify the issue with the EGT Sensor 3 Circuit.
  2. Inspect Wiring: Check the wiring connections to the EGT sensor for any damage or corrosion and repair or replace as needed.
  3. Replace EGT Sensor: If the sensor is faulty, replace it with a new one following manufacturer's guidelines.
  4. Repair Exhaust Leaks: Inspect the exhaust system for leaks and repair any found leaks to ensure accurate sensor readings.
  5. Clear Codes: After completing the repairs, clear the DTC and test drive the vehicle to ensure the issue has been resolved.

Cost to Fix P242D GMC

The typical cost for repairing an Exhaust Gas Temperature Sensor 3 Circuit High Voltage issue can vary depending on the specific vehicle make and model, as well as the labor rates in your area. However, you can expect to pay anywhere from $150 to $400 for parts and labor. Keep in mind that diagnostic time and labor rates can vary, so it's best to check with local auto repair shops for a more accurate estimate.

What does this mean?

Tech Notes for P242D GMC

After starting the engine, the exhaust gas temperature sensor temperature should rise steadily, then stabilize after the engine reaches operating temperature. Exhaust gas temperature sensors may fail intermittently while operating under extreme temperatures. Review the Freeze Frame/Failure Records to verify the failure criteria.

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Information for Specific GMC Models

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 P242D GMC Code

1. What are common symptoms of OBDII code P242D GMC related to the Exhaust Gas Temperature Sensor 3 Circuit High Voltage?

The common symptoms include the illumination of the check engine light, reduced engine performance, and potential issues with fuel efficiency.

2. What are the possible causes of OBDII code P242D GMC indicating Exhaust Gas Temperature Sensor 3 Circuit High Voltage?

The code P242D GMC can be triggered by a faulty exhaust gas temperature sensor, wiring issues, a damaged sensor connector, or problems with the sensor circuit.

3. How can I diagnose the OBDII code P242D GMC related to the Exhaust Gas Temperature Sensor 3 Circuit High Voltage?

Diagnosing this code typically involves using an OBDII scanner to retrieve the code, inspecting the exhaust gas temperature sensor and its wiring for any visible damage, and testing the sensor's voltage and resistance.

4. Can I continue driving my vehicle with OBDII code P242D GMC active?

It is not recommended to drive your vehicle with the code P242D GMC present, as it can lead to further damage to the engine or emissions system. It is best to address the issue promptly.

5. What are the repair options for OBDII code P242D GMC related to the Exhaust Gas Temperature Sensor 3 Circuit High Voltage?

Repair options may include replacing the faulty exhaust gas temperature sensor, repairing or replacing damaged wiring, checking and cleaning the sensor connector, and clearing the trouble code with an OBDII scanner.

6. Is it possible to reset the OBDII code P242D GMC without fixing the underlying issue?

While it is possible to clear the code temporarily, it will likely reappear if the underlying issue causing the high voltage condition in the exhaust gas temperature sensor is not addressed.

7. How critical is it to fix OBDII code P242D GMC indicating Exhaust Gas Temperature Sensor 3 Circuit High Voltage?

It is important to address the code promptly to prevent potential damage to the engine or emissions system, as well as to ensure optimal performance and fuel efficiency of the vehicle.

8. Can a DIY enthusiast repair OBDII code P242D GMC on their own?

Depending on the individual's level of automotive repair knowledge and experience, some DIY enthusiasts may be able to address this code by following repair guides and using the necessary tools.

9. Are there any preventive measures to avoid triggering OBDII code P242D GMC in the future?

Regular vehicle maintenance, such as checking the exhaust system components and sensors during scheduled services, can help prevent issues that may trigger the code P242D GMC.

10. How long does it typically take to repair OBDII code P242D GMC related to the Exhaust Gas Temperature Sensor 3 Circuit High Voltage?

The repair time can vary depending on the exact cause of the code and the complexity of the repair. It may take anywhere from a few hours to a full day to diagnose and fix the issue.

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