Engine-CodesGMC – P1118 GMC

P1118 GMC Code - Engine Coolant Temp. Signal Out-Of-Range High

Quick Answer

The P1118 GMC code indicates that the Engine Coolant Temperature (ECT) sensor is sending a signal that is out-of-range high to the engine control module (ECM). Common causes include Faulty ECT sensor, Corroded or damaged ECT sensor wiring, Poor electrical connection at the ECT sensor. 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
P1118 GMC indicates Engine Coolant Temp. Signal Out-Of-Range High.
Common causes
Common causes include Faulty ECT sensor, Corroded or damaged ECT sensor wiring, Poor electrical connection at the ECT sensor.
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 10, 2024
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Code P1118 GMC Description

The P1118 GMC code indicates that the Engine Coolant Temperature (ECT) sensor is sending a signal that is out-of-range high to the engine control module (ECM). The ECT sensor is a crucial component that monitors the temperature of the engine coolant. This information is essential for the ECM to adjust fuel delivery and ignition timing to ensure optimal engine performance and efficiency. When the ECT sensor signal is out-of-range high, it means that the engine coolant temperature is higher than what is expected under normal operating conditions.

OBDII Code P1118 GMC - Engine Coolant Temp. Signal Out-Of-Range High
P1118 GMC Code - Engine Coolant Temp. Signal Out-Of-Range High

Common Causes of P1118 GMC

  1. Faulty ECT sensor
  2. Corroded or damaged ECT sensor wiring
  3. Poor electrical connection at the ECT sensor
  4. ECM malfunction
  5. Coolant system leak or low coolant level

Symptoms of P1118 GMC

  1. Check Engine Light illuminated
  2. Engine running hotter than normal
  3. Poor fuel economy
  4. Decreased engine performance
  5. Rough idling or stalling

How to Fix P1118 GMC

  1. Begin by diagnosing the issue using a scan tool to read the code and check the ECT sensor data.
  2. Inspect the ECT sensor and its wiring for any visible damage or corrosion. Replace the sensor if necessary.
  3. Check the coolant level and system for leaks. Top up the coolant if low and repair any leaks.
  4. Test the ECT sensor circuit for proper voltage and resistance. Repair any wiring or connector issues.
  5. Clear the code and test drive the vehicle to ensure the issue has been resolved.

Cost to Fix P1118 GMC

The cost of repairing a P1118 GMC code can vary depending on the specific cause of the issue. In general, the cost of replacing a faulty ECT sensor can range from $50 to $150, while addressing wiring or connector problems may add to the total cost. Labor costs can also vary, with typical hourly rates ranging from $80 to $150. It is advisable to consult with a certified mechanic to get a more accurate estimate based on the specific vehicle make and model.

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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.

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