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P0668 Chevrolet Code - Control Module Temperature Sensor Circuit Low Voltage

Quick Answer

The P0668 code for Chevrolet vehicles indicates an issue with the Control Module Temperature Sensor Circuit registering low voltage. Common causes include Faulty Temperature Sensor: The most common cause of the P0668 code is a faulty control module temperature sensor that is not accurately detecting temperature fluctuations, Wiring Issues: Corrosion, damage, or loose connections in the wiring harness connected to the temperature sensor can disrupt the voltage readings and trigger the code, Control Module Malfunction: A malfunction in the control module itself can also lead to low voltage readings from the temperature sensor circuit. 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 Temperature Sensor: The most common cause of the P0668 code is a faulty control module temperature sensor that is not accurately detecting temperature fluctuations, Wiring Issues: Corrosion, damage, or loose connections in the wiring harness connected to the temperature sensor can disrupt the voltage readings and trigger the code, Control Module Malfunction: A malfunction in the control module itself can also lead to low voltage readings from the temperature sensor circuit.
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.
What is this?
Table of contents Created and updated by William Orellana on Sep 12, 2024
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Code P0668 Chevrolet Description

The P0668 code for Chevrolet vehicles indicates an issue with the Control Module Temperature Sensor Circuit registering low voltage. This sensor is responsible for monitoring the temperature of the control module, which is crucial for the proper functioning of various systems in the vehicle. The control module plays a key role in regulating engine performance, emissions, and overall vehicle operation. When the sensor circuit detects low voltage, it can lead to a range of performance issues and potentially cause long-term damage if not addressed promptly.

OBDII Code P0668 Chevrolet - Control Module Temperature Sensor Circuit Low Voltage
P0668 Chevrolet Code - Control Module Temperature Sensor Circuit Low Voltage

Common Causes of P0668 Chevrolet

  1. Faulty Temperature Sensor: The most common cause of the P0668 code is a faulty control module temperature sensor that is not accurately detecting temperature fluctuations.
  2. Wiring Issues: Corrosion, damage, or loose connections in the wiring harness connected to the temperature sensor can disrupt the voltage readings and trigger the code.
  3. Control Module Malfunction: A malfunction in the control module itself can also lead to low voltage readings from the temperature sensor circuit.
  4. Environmental Factors: Exposure to extreme temperatures, moisture, or debris in the engine compartment can also affect the performance of the temperature sensor and trigger the code.
  5. Electrical Problems: Issues with the vehicle's electrical system, such as a blown fuse or a short circuit, can disrupt the voltage supply to the sensor and cause the code to appear.

Symptoms of P0668 Chevrolet

  1. Check Engine Light: The most common symptom associated with the P0668 code is the illumination of the check engine light on the dashboard. This serves as an indication that there is a problem with the control module temperature sensor circuit.
  2. Poor Engine Performance: A malfunctioning temperature sensor can result in poor engine performance, including rough idling, stalling, or hesitation during acceleration.
  3. Decreased Fuel Efficiency: Issues with the control module temperature sensor can also lead to decreased fuel efficiency, as the engine may not be operating at optimal temperatures.
  4. Overheating: In some cases, a faulty sensor can cause the engine to overheat due to incorrect temperature readings, posing a risk of damage to the vehicle.
  5. Difficulty Starting: A problematic control module temperature sensor can also cause difficulty starting the vehicle, as it may struggle to maintain proper engine temperatures.

How to Fix P0668 Chevrolet

  1. Diagnostic Scan: The first step in addressing the P0668 code is to perform a diagnostic scan to confirm the specific cause of the issue and pinpoint the faulty component.
  2. Check Wiring: Inspect the wiring harness connected to the control module temperature sensor for any signs of damage, corrosion, or loose connections. Repair or replace any faulty wiring as needed.
  3. Test Temperature Sensor: Test the control module temperature sensor to ensure it is accurately detecting temperature changes. Replace the sensor if it is found to be faulty.
  4. Check Control Module: Inspect the control module for any signs of malfunction or damage. If necessary, replace the control module to resolve the low voltage issue.
  5. Clear Codes: After completing the repairs, clear the diagnostic trouble codes from the vehicle's system and test drive the vehicle to ensure that the issue has been resolved.

Cost to Fix P0668 Chevrolet

The typical repair costs for addressing the P0668 code on a Chevrolet vehicle can vary depending on the specific cause of the issue and the extent of repairs needed. In general, the cost of replacing a faulty control module temperature sensor can range from $100 to $250, including parts and labor. If additional repairs are required, such as fixing wiring issues or replacing the control module, the total cost could increase accordingly. It's important to note that the cost of diagnosis and labor rates at auto repair shops can vary significantly, so it's advisable to obtain quotes from multiple sources to get an accurate estimate for the repair.

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Information for Specific Chevrolet Models

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.

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