AutoCodes – GMC – P118F 2018 GMC Sierra

P118F 2018 GMC Sierra Code - Exhaust Gas Temperature Sensor 2 Performance Engine Running

Quick Answer

The exhaust gas temperature sensors are variable resistors that measure the temperature of the exhaust gas. Common causes include Faulty Exhaust Gas Temperature Sensor, Exhaust Gas Temperature Sensor harness is open or shorted, Exhaust Gas Temperature Sensor 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: P118F 2018 GMC Sierra indicates Exhaust Gas Temperature Sensor 2 Performance Engine Running.
Common causes: Common causes include Faulty Exhaust Gas Temperature Sensor, Exhaust Gas Temperature Sensor harness is open or shorted, Exhaust Gas Temperature Sensor 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 218

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 Mar 29, 2024

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P118F 2018 GMC Sierra Description

The exhaust gas temperature sensors are variable resistors that measure the temperature of the exhaust gas. The exhaust temperature sensor 1 is the first exhaust temperature sensor on 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 be set if the ECM detects that the difference between measured exhaust gas temperature and the estimated exhaust gas temperature is greater than a calibrated amount for greater than 1 s.

OBDII Code P118F 2018 GMC Sierra - Exhaust Gas Temperature Sensor 2 Performance Engine Running - AutoCodes.com — P118F 2018 GMC Sierra Code - Exhaust Gas Temperature Sensor 2 Performance Engine Running

What does this mean?

What are the Possible Causes of the DTC P118F 2018 GMC Sierra?

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

How to Fix the DTC P118F 2018 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 is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P118F 2018 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 P118F 2018 GMC Sierra code?

Need more information on how to fix the P118F 2018 GMC Sierra code? Get Access to Factory Service Manuals

Need Help with the Code?

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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 P118F 2018 GMC Sierra Code

1. What does the OBDII code P118F mean on a 2018 GMC Sierra?

P118F indicates a performance issue with Exhaust Gas Temperature (EGT) Sensor 2 while the engine is running. This sensor monitors exhaust temperatures to optimize emissions and engine performance.

2. What are the common symptoms of the P118F code?

Symptoms may include an illuminated check engine light, reduced engine performance, poor fuel efficiency, and potential emissions test failure.

3. What causes the P118F code to appear?

Common causes include a faulty EGT sensor 2, damaged wiring or connectors, excessive soot buildup on the sensor, or an exhaust system issue affecting sensor performance.

4. Can driving with the P118F code damage my 2018 GMC Sierra?

While it may not cause immediate damage, prolonged driving with this code can lead to increased emissions, reduced fuel efficiency, and potential damage to the exhaust system or catalytic converter.

5. How do I diagnose the P118F code?

Start by scanning for codes with an OBDII scanner, inspecting the wiring and connectors for damage, and testing the EGT sensor 2 for proper voltage and resistance readings.

6. How do I fix the P118F code on my GMC Sierra?

Repairs may include replacing the faulty EGT sensor 2, cleaning soot buildup, repairing damaged wiring or connectors, or addressing any exhaust system issues.

7. Is the P118F code specific to EGT Sensor 2?

Yes, the code specifically refers to a performance issue with Exhaust Gas Temperature Sensor 2, which is typically located downstream in the exhaust system.

8. How much does it cost to repair the P118F code?

The cost varies depending on the issue. Replacing an EGT sensor typically costs $100-$300, while wiring repairs or exhaust system fixes may cost more.

9. Can a software update fix the P118F code?

In rare cases, a software update to the engine control module (ECM) may resolve the issue if itâ€™s related to programming. Consult a dealership or qualified mechanic to confirm.

10. How can I prevent the P118F code from recurring?

Regular maintenance, such as keeping the exhaust system clean, inspecting wiring and connectors, and performing periodic checks on sensors, can help prevent this code from reoccurring.