AutoCodes – GMC – P242D 2015 GMC Sierra

P242D 2015 GMC Sierra Code - Exhaust Gas Temperature Sensor 3 Circuit High Voltage

Quick Answer

The Exhaust Gas Temperature sensors (EGTS) are variable resistors that measure the temperature of the exhaust gas. Common causes include Faulty Exhaust Gas Temperature Sensor (EGTS) 3, Exhaust Gas Temperature Sensor 3 harness is open or shorted, Exhaust Gas Temperature Sensor 3 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: P242D 2015 GMC Sierra indicates Exhaust Gas Temperature Sensor 3 Circuit High Voltage.
Common causes: Common causes include Faulty Exhaust Gas Temperature Sensor (EGTS) 3, Exhaust Gas Temperature Sensor 3 harness is open or shorted, Exhaust Gas Temperature Sensor 3 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 204

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 Jul 03, 2022

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code P242D 2015 GMC Sierra Description

The Exhaust Gas Temperature sensors (EGTS) are variable resistors that measure the temperature of the exhaust gas. Exhaust temperature sensor 1 is the first exhaust temperature sensor in the exhaust system, the following exhaust temperature sensors are counted upward from the engine outlet to the exhaust system end. The Engine Control Module (ECM) supplies 5 V to the exhaust gas temperature signal circuit and supplies a ground to the low reference circuit. The exhaust gas temperature sensor temperature information is used by the ECM during the exhaust gas particulate filter cleaning process. The Diagnostic Trouble Code (DTC) will ve set when the ECM detects that the exhaust gas temperature sensor is greater than 900 Ω for greater than 2 s.

OBDII Code P242D 2015 GMC Sierra - Exhaust Gas Temperature Sensor 3 Circuit High Voltage - AutoCodes.com — P242D 2015 GMC Sierra Code - Exhaust Gas Temperature Sensor 3 Circuit High Voltage

What does this mean?

What are the Possible Causes of the DTC P242D 2015 GMC Sierra?

Faulty Exhaust Gas Temperature Sensor (EGTS) 3
Exhaust Gas Temperature Sensor 3 harness is open or shorted
Exhaust Gas Temperature Sensor 3 circuit poor electrical connection
Faulty Engine Control Module (ECM)

How to Fix the DTC P242D 2015 GMC Sierra?

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

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.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P242D 2015 GMC Sierra 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.

Need more information about the P242D 2015 GMC Sierra code?

Need more information on how to fix the P242D 2015 GMC Sierra code? Get Access to Factory Service Manuals

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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 P242D 2015 GMC Sierra Code

1. What does the OBDII code P242D mean on a 2015 GMC Sierra?

P242D indicates a high voltage issue in the Exhaust Gas Temperature (EGT) Sensor 3 Circuit, which monitors exhaust temperatures to help regulate emissions and protect components.

2. What are the symptoms of code P242D on a 2015 GMC Sierra?

Common symptoms include the check engine light turning on, reduced fuel efficiency, possible engine performance issues, and improper emissions system operation.

3. What causes the P242D code to appear in a 2015 GMC Sierra?

Potential causes include a faulty EGT sensor, damaged wiring or connectors, excessive soot buildup on the sensor, or an issue with the vehicle's PCM (powertrain control module).

4. Can I drive my 2015 GMC Sierra with a P242D code?

Driving with this code is not recommended, as it could affect emissions system performance and potentially lead to further damage to the exhaust system or related components.

5. How do I fix the P242D code on my GMC Sierra?

Repair steps may include inspecting and repairing damaged wiring, cleaning or replacing the EGT sensor, and, in rare cases, reprogramming or replacing the PCM.

6. Where is Exhaust Gas Temperature Sensor 3 located on a 2015 GMC Sierra?

Sensor 3 is typically located in the exhaust system, downstream of the diesel particulate filter (DPF), but exact placement can vary depending on the engine configuration.

7. How much does it cost to fix the P242D code on a 2015 GMC Sierra?

Repair costs can range from $100 to $300 for sensor replacement, with additional costs if wiring repairs or PCM replacement is needed.

8. Can a dirty exhaust system cause the P242D code?

Yes, excessive soot or carbon buildup in the exhaust system can interfere with the EGT sensor's readings and trigger the code.

9. Do I need to replace the EGT sensor to clear the P242D code?

Not always. First, inspect the wiring and connections. If no damage is found, cleaning the sensor or verifying its functionality may resolve the issue without replacement.

10. Will resetting the check engine light fix the P242D code?

Resetting the light will clear the code temporarily, but if the underlying issue isnâ€™t fixed, the code will likely return. Always address the root cause of the problem.