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Engine-Codes – GMC – P242C GMC

P242C GMC Code - Exhaust Gas Temperature Sensor 3 Circuit Low Voltage

Quick Answer

The P242C GMC code indicates a problem with the Exhaust Gas Temperature Sensor 3 Circuit, specifically that the voltage is too low. Common causes include Faulty Sensor: The most common cause of this code is a malfunctioning Exhaust Gas Temperature Sensor 3, Wiring Issues: Damaged or corroded wiring connections to the sensor can also trigger this code, Exhaust System Leak: A leak in the exhaust system can affect the sensor's readings and trigger a low voltage 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
P242C GMC indicates Exhaust Gas Temperature Sensor 3 Circuit Low Voltage.
Common causes
Common causes include Faulty Sensor: The most common cause of this code is a malfunctioning Exhaust Gas Temperature Sensor 3, Wiring Issues: Damaged or corroded wiring connections to the sensor can also trigger this code, Exhaust System Leak: A leak in the exhaust system can affect the sensor's readings and trigger a low voltage 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 P242C GMC Description

The P242C GMC code indicates a problem with the Exhaust Gas Temperature Sensor 3 Circuit, specifically that the voltage is too low. This sensor is responsible for monitoring the exhaust gas temperature and providing crucial data to the engine control module for optimal performance and emissions control. When the voltage is low, it can lead to inaccurate readings and potentially affect the engine's performance, fuel efficiency, and emissions output.

OBDII Code P242C GMC - Exhaust Gas Temperature Sensor 3 Circuit Low Voltage
P242C GMC Code - Exhaust Gas Temperature Sensor 3 Circuit Low Voltage

Common Causes of P242C GMC

  1. Faulty Sensor: The most common cause of this code is a malfunctioning Exhaust Gas Temperature Sensor 3.
  2. Wiring Issues: Damaged or corroded wiring connections to the sensor can also trigger this code.
  3. Exhaust System Leak: A leak in the exhaust system can affect the sensor's readings and trigger a low voltage code.
  4. Engine Control Module (ECM) Failure: A malfunctioning ECM can also cause issues with the EGT sensor readings.

Symptoms of P242C GMC

  1. Check Engine Light: The most common symptom associated with this code is the illumination of the check engine light on the dashboard.
  2. Reduced Power: The vehicle may experience a decrease in power or acceleration due to the sensor's inaccurate readings.
  3. Poor Fuel Economy: A faulty EGT sensor can cause the engine to run rich or lean, leading to decreased fuel efficiency.
  4. Rough Idling: The engine may idle rough or inconsistently if the sensor is not functioning properly.

How to Fix P242C GMC

  1. Diagnose the Issue: Use a diagnostic scanner to retrieve the trouble code and perform further testing to identify the exact cause of the low voltage.
  2. Replace the Sensor: If the EGT sensor is faulty, it will need to be replaced with a new one.
  3. Check Wiring: Inspect the wiring harness for any damage or corrosion and repair or replace as needed.
  4. Repair Exhaust Leak: If an exhaust leak is detected, it should be repaired to ensure accurate sensor readings.
  5. Reset the Code: After completing the repairs, clear the diagnostic trouble codes and test drive the vehicle to ensure the issue has been resolved.

Cost to Fix P242C GMC

The cost of repairing a P242C GMC code can vary depending on the specific cause of the issue and the labor rates in your area. Typically, the cost of a new Exhaust Gas Temperature Sensor 3 can range from $50 to $150, while labor costs can be around $100 to $200. Overall, you can expect to pay anywhere from $150 to $350 for this repair, but it's advisable to get a detailed quote from a local auto repair shop for a more accurate estimate.

What does this mean?

Tech Notes for P242C 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 P242C GMC Code

1. What are the common symptoms of OBDII code P242C GMC (Exhaust Gas Temperature Sensor 3 Circuit Low Voltage)?

The common symptoms of this code may include poor engine performance, increased fuel consumption, and the illumination of the Check Engine Light.

2. What could cause the OBDII code P242C GMC to trigger?

The trigger of code P242C GMC is often caused by a faulty exhaust gas temperature sensor, damaged wiring or connectors, or issues with the sensor circuit.

3. How can I diagnose the OBDII code P242C GMC at home?

You can diagnose the code P242C GMC at home using an OBDII scanner to read the trouble codes and checking the exhaust gas temperature sensor and its wiring for any visible damage.

4. Is it safe to continue driving with the OBDII code P242C GMC present?

It is not recommended to continue driving with the code P242C GMC present, as it can lead to further damage to the vehicle and may result in poor engine performance.

5. Can I repair the OBDII code P242C GMC myself?

Repairing the code P242C GMC may require some technical knowledge and tools. If you are familiar with automotive repairs, you may be able to replace the exhaust gas temperature sensor or repair any damaged wiring yourself.

6. How much does it cost to repair the OBDII code P242C GMC at a repair shop?

The cost of repairing the code P242C GMC at a repair shop can vary depending on the extent of the damage and the labor rates in your area. It is advisable to get a few quotes from different shops.

7. Will resetting the Check Engine Light make the OBDII code P242C GMC go away?

Resetting the Check Engine Light will temporarily turn off the light, but it will not fix the underlying issue causing the code. The code is likely to return until the root cause is addressed.

8. What are some tips to prevent the OBDII code P242C GMC from reoccurring?

To prevent the code P242C GMC from reoccurring, it is important to regularly maintain your vehicle, check the condition of sensors and wiring, and address any issues promptly.

9. How urgent is it to address the OBDII code P242C GMC?

It is recommended to address the code P242C GMC as soon as possible to prevent further damage to your vehicle and ensure optimal engine performance.

10. Can the OBDII code P242C GMC be related to other engine issues?

While the code P242C GMC specifically relates to the exhaust gas temperature sensor circuit, it can also be related to other engine issues such as fuel system problems or sensor malfunctions.

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