Engine-CodesGMC – P101C 2018 GMC Sierra

P101C 2018 GMC Sierra Code - Glow Plug Control Module Temperature Sensor 2 Circuit High Voltage

Quick Answer

The P101C diagnostic trouble code (DTC) for a 2018 GMC Sierra refers to the Glow Plug Control Module Temperature Sensor 2 Circuit High Voltage. Common causes include Faulty glow plug control module temperature sensor, Short circuit or open circuit in the temperature sensor circuit, Corrosion or poor connection in the wiring harness. 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
P101C 2018 GMC Sierra indicates Glow Plug Control Module Temperature Sensor 2 Circuit High Voltage.
Common causes
Common causes include Faulty glow plug control module temperature sensor, Short circuit or open circuit in the temperature sensor circuit, Corrosion or poor connection in the wiring harness.
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.
Table of contents Created and updated by William Orellana on Sep 15, 2024
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Code P101C 2018 GMC Sierra Description

The P101C diagnostic trouble code (DTC) for a 2018 GMC Sierra refers to the Glow Plug Control Module Temperature Sensor 2 Circuit High Voltage. This code indicates that there is a high voltage condition detected in the temperature sensor circuit of the glow plug control module. The glow plug control module is responsible for managing the glow plugs in a diesel engine, which are used to heat the combustion chamber for easier cold starts. The temperature sensor monitors the temperature of the glow plug control module to ensure proper operation.

OBDII Code P101C 2018 GMC Sierra - Glow Plug Control Module Temperature Sensor 2 Circuit High Voltage
P101C 2018 GMC Sierra Code - Glow Plug Control Module Temperature Sensor 2 Circuit High Voltage

Common Causes of P101C 2018 GMC Sierra

  1. Faulty glow plug control module temperature sensor.
  2. Short circuit or open circuit in the temperature sensor circuit.
  3. Corrosion or poor connection in the wiring harness.
  4. Electrical issues such as a blown fuse or relay related to the glow plug system.
  5. Software or programming issues with the engine control module (ECM).

Symptoms of P101C 2018 GMC Sierra

  1. Difficult or hard starting, especially in cold weather.
  2. Rough idling or misfiring engine.
  3. Decreased fuel efficiency.
  4. Increased emissions.
  5. Illumination of the check engine light on the dashboard.

How to Fix P101C 2018 GMC Sierra

  1. Begin by verifying the DTC and conducting a thorough inspection of the glow plug control module temperature sensor and circuit.
  2. Test the temperature sensor for proper resistance values and functionality.
  3. Check the wiring harness for any signs of damage, corrosion, or poor connections.
  4. Replace the glow plug control module temperature sensor if it is found to be faulty.
  5. Clear the DTC and perform a test drive to ensure the issue has been resolved.

Cost to Fix P101C 2018 GMC Sierra

The typical repair costs for addressing a P101C code on a 2018 GMC Sierra can range from $200 to $500, including parts and labor. However, it's important to note that actual costs may vary depending on the specific diagnosis time and labor rates at auto repair shops. Rates can range from $80 to $150 per hour, with higher rates in metropolitan areas or at dealerships and lower rates at independent shops. It's recommended to obtain quotes from local shops for a more accurate estimate.

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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 P101C 2018 GMC Sierra Code

1. What are the common symptoms of OBDII code P101C in a 2018 GMC Sierra related to the Glow Plug Control Module Temperature Sensor 2 Circuit High Voltage?

The common symptoms include the Check Engine Light illuminating on the dashboard, reduced engine performance, and potential difficulties starting the vehicle.

2. What are the possible causes of OBDII code P101C in a 2018 GMC Sierra?

Possible causes of this code can include a faulty glow plug control module, a malfunctioning temperature sensor, wiring issues, or a poor electrical connection.

3. How can I diagnose the Glow Plug Control Module Temperature Sensor 2 Circuit High Voltage issue in my 2018 GMC Sierra?

To diagnose this issue, you can use an OBDII scanner to read the specific fault code, visually inspect the wiring and connections related to the sensor, and test the sensor's resistance and voltage.

4. Can I continue driving my 2018 GMC Sierra with OBDII code P101C active?

It's not recommended to drive with this code active, as it can lead to further engine problems and potential safety issues. It's best to address the underlying cause as soon as possible.

5. How can I repair OBDII code P101C in my 2018 GMC Sierra?

The repair process may involve replacing the faulty glow plug control module, temperature sensor, or repairing any damaged wiring or connections. It's advisable to consult a professional mechanic for an accurate diagnosis and repair.

6. Are there any DIY tips for troubleshooting OBDII code P101C in a 2018 GMC Sierra?

You can start by checking the sensor's connections and wiring for any visible damage or corrosion. Additionally, ensure the sensor is receiving the correct voltage and resistance values as per the manufacturer's specifications.

7. Can extreme weather conditions affect the Glow Plug Control Module Temperature Sensor 2 Circuit in a 2018 GMC Sierra?

Yes, extreme weather conditions, especially cold temperatures, can put additional strain on the glow plug system, potentially leading to issues with the temperature sensor circuit.

8. Will resetting the OBDII code P101C in my 2018 GMC Sierra make the problem go away permanently?

Simply resetting the code may temporarily turn off the Check Engine Light, but if the underlying issue causing the fault code is not addressed, the code is likely to reappear.

9. Is it necessary to replace the Glow Plug Control Module Temperature Sensor 2 Circuit components if OBDII code P101C is triggered in a 2018 GMC Sierra?

Depending on the diagnostic results, it may be necessary to replace the faulty components to resolve the issue and prevent further engine problems. Consult a mechanic for a proper assessment.

10. How important is it to address OBDII code P101C promptly in a 2018 GMC Sierra?

It's crucial to address this code promptly to prevent potential damage to the engine and ensure the vehicle operates efficiently. Ignoring the issue may lead to more severe problems down the road.

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