AutoCodes – GMC – P1117 GMC

P1117 GMC Code - Engine Coolant Temperature Signal Out-Of-Range Low

Quick Answer

The Engine Coolant Temperature (ECT) sensor contains a semiconductor device which changes resistance based on temperature (a thermistor). Common causes include Low engine coolant level, Faulty Engine Coolant Temperature (ECT) sensor, Engine Coolant Temperature (ECT) sensor harness is open or shorted. 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: P1117 GMC indicates Engine Coolant Temperature Signal Out-Of-Range Low.
Common causes: Common causes include Low engine coolant level, Faulty Engine Coolant Temperature (ECT) sensor, Engine Coolant Temperature (ECT) sensor harness is open or shorted.
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 3,868

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Intermediate (2 / 3)

What is this?

Table of contents Created and updated by William Orellana on Apr 22, 2019

Description
Possible Causes
How To Fix
Cost to Diagnose
Comments
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Code P1117 GMC Description

The Engine Coolant Temperature (ECT) sensor contains a semiconductor device which changes resistance based on temperature (a thermistor). The ECT sensor mounts in the left bank cylinder head near the front of the engine. The ECT sensor has a signal circuit and a ground circuit. The Powertrain Control Module (PCM) applies a voltage (about 5.0 volts) on the signal circuit to the sensor. The PCM monitors changes in this voltage caused by changes in the resistance of the sensor in order to determine the engine coolant temperature.
When the engine coolant is cold, the sensor (thermistor) resistance is high, and the PCMs signal voltage is only pulled down a small amount through the sensor to ground. The PCM senses a high signal voltage (low temperature). When the engine coolant is warm, the sensor resistance is low, and the signal voltage is pulled down a greater amount. This causes the PCM to sense a low signal voltage (high temperature).

OBDII Code P1117 GMC - Engine Coolant Temperature Signal Out-Of-Range Low - AutoCodes.com — P1117 GMC Code - Engine Coolant Temperature Signal Out-Of-Range Low

What does this mean?

What are the Possible Causes of the DTC P1117 GMC?

Low engine coolant level
Faulty Engine Coolant Temperature (ECT) sensor
Engine Coolant Temperature (ECT) sensor harness is open or shorted
Engine Coolant Temperature (ECT) sensor electrical circuit poor connection
Faulty engine coolant thermostat

How to Fix the DTC P1117 GMC?

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 P1117 GMC 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.

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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.