AutoCodes – Chevrolet – P0668 Chevrolet

P0668 Chevrolet Code - Control Module Temperature Sensor Circuit Low Voltage

Quick Answer

The Transmission Control Module (TCM) temperature sensor is located inside of the control solenoid valve assembly which has no serviceable parts. Common causes include Faulty Control Solenoid Valve Assembly, Control Solenoid Valve Assembly harness is open or shorted, Control Solenoid Valve Assembly 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: P0668 Chevrolet indicates Control Module Temperature Sensor Circuit Low Voltage.
Common causes: Common causes include Faulty Control Solenoid Valve Assembly, Control Solenoid Valve Assembly harness is open or shorted, Control Solenoid Valve Assembly 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 428

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 Sep 23, 2022

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P0668 Chevrolet Description

The Transmission Control Module (TCM) temperature sensor is located inside of the control solenoid valve assembly which has no serviceable parts. The Transmission Control Module temperature sensor provides the temperature of the Transmission Control Module substrate. This temperature reading is used in various diagnostic routines in the Transmission Control Module software. This fault is handled inside the Transmission Control Module and no external circuits are involved. The Diagnostic Trouble Code (DTC) will be set when the TCM internal temperature is −249°C (−416°F) or less for 1 min.

OBDII Code P0668 Chevrolet - Control Module Temperature Sensor Circuit Low Voltage - AutoCodes.com — P0668 Chevrolet Code - Control Module Temperature Sensor Circuit Low Voltage

What does this mean?

What are the Possible Causes of the DTC P0668 Chevrolet?

Faulty Control Solenoid Valve Assembly
Control Solenoid Valve Assembly harness is open or shorted
Control Solenoid Valve Assembly circuit poor electrical connection

How to Fix the DTC P0668 Chevrolet?

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 P0668 Chevrolet 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 P0668 Chevrolet code?

Need more information on how to fix the P0668 Chevrolet code? Get Access to Factory Service Manuals

Need Help with the Code?

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Information for Specific Chevrolet Models

P0668 2014 Chevrolet Silverado — Control Module Temperature Sensor Circuit Low Voltage
P0668 2015 Chevrolet Silverado — Control Module Temperature Sensor Circuit Low Voltage
P0668 2016 Chevrolet Silverado — Control Module Temperature Sensor Circuit Low Voltage
P0668 2017 Chevrolet Silverado — Control Module Temperature Sensor Circuit Low Voltage
P0668 2018 Chevrolet Silverado — Control Module Temperature Sensor Circuit Low Voltage

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 P0668 Chevrolet Code

1. What does the OBDII code P0668 mean on a Chevrolet?

P0668 indicates a "Control Module Temperature Sensor Circuit Low Voltage," meaning the vehicle's control module has detected an abnormally low voltage in the temperature sensor circuit.

2. What are the common symptoms of the P0668 code in a Chevrolet?

Symptoms may include engine stalling, poor performance, difficulty starting, an illuminated Check Engine Light, or erratic temperature readings.

3. What causes the P0668 code to appear in a Chevrolet?

Common causes include a faulty control module temperature sensor, damaged or corroded wiring or connectors, a short circuit, or issues with the powertrain control module (PCM).

4. Can I drive my Chevrolet with the P0668 code?

While the vehicle may still be drivable, it can lead to performance issues or further damage. It's best to address the problem as soon as possible.

5. How do I fix the P0668 code on my Chevrolet?

Repairs may include inspecting and repairing wiring or connectors, replacing the control module temperature sensor, or reprogramming or replacing the PCM if necessary.

6. How can I diagnose the P0668 code in my Chevrolet?

Diagnosis involves using an OBDII scanner to confirm the code, visually inspecting the sensor, wiring, and connectors, and testing the voltage and resistance of the sensor circuit.

7. Can a bad control module temperature sensor cause the P0668 code?

Yes, a malfunctioning sensor can trigger the P0668 code by sending incorrect or no voltage signals to the PCM.

8. How much does it cost to fix the P0668 code on a Chevrolet?

Repair costs can range from $50 to $200 for parts like sensors or wiring repairs, but PCM replacement or reprogramming may cost $500 or more.

9. Will clearing the P0668 code fix the issue?

Clearing the code with an OBDII scanner will erase it temporarily, but the issue will return unless the underlying problem is resolved.

10. Can a low battery cause the P0668 code in a Chevrolet?

Yes, a weak or failing battery can result in low voltage and potentially trigger the P0668 code. Ensure the battery is in good condition before further diagnostics.