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P0668 Buick Code - Control Module Temperature Sensor Circuit Low Voltage

Quick Answer

The P0668 Buick code indicates a problem with the Control Module Temperature Sensor Circuit, specifically detecting low voltage. Common causes include Faulty Temperature Sensor: The most common cause of this code is a malfunctioning control module temperature sensor, Damaged Wiring: Corrosion, breaks, or shorts in the wiring connecting the temperature sensor to the control module can cause low voltage readings, Poor Electrical Connection: Loose or corroded connectors in the circuit can disrupt the flow of voltage and trigger the code. 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 Buick indicates Control Module Temperature Sensor Circuit Low Voltage.
Common causes
Common causes include Faulty Temperature Sensor: The most common cause of this code is a malfunctioning control module temperature sensor, Damaged Wiring: Corrosion, breaks, or shorts in the wiring connecting the temperature sensor to the control module can cause low voltage readings, Poor Electrical Connection: Loose or corroded connectors in the circuit can disrupt the flow of voltage and trigger the code.
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 Buick Description

The P0668 Buick code indicates a problem with the Control Module Temperature Sensor Circuit, specifically detecting low voltage. The Control Module Temperature Sensor is responsible for monitoring the temperature of various components within the vehicle, such as the engine, transmission, or even the control module itself. When the sensor detects that the voltage is lower than the expected range, it triggers this diagnostic trouble code (DTC).

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

Common Causes of P0668 Buick

  1. Faulty Temperature Sensor: The most common cause of this code is a malfunctioning control module temperature sensor.
  2. Damaged Wiring: Corrosion, breaks, or shorts in the wiring connecting the temperature sensor to the control module can cause low voltage readings.
  3. Poor Electrical Connection: Loose or corroded connectors in the circuit can disrupt the flow of voltage and trigger the code.
  4. Control Module Issues: A malfunctioning control module can also cause low voltage readings from the temperature sensor.

Symptoms of P0668 Buick

  1. Check Engine Light: The most common symptom associated with this code is the illumination of the check engine light on the vehicle's dashboard.
  2. Poor Fuel Economy: A malfunctioning temperature sensor can lead to incorrect fuel mixture adjustments, resulting in decreased fuel efficiency.
  3. Engine Performance Issues: The vehicle may experience rough idling, hesitation, or lack of power due to the control module receiving inaccurate temperature readings.
  4. Overheating: In some cases, the engine may overheat due to the control module not receiving accurate temperature data, leading to potential damage.

How to Fix P0668 Buick

  1. Diagnostic Testing: Begin by using a diagnostic scanner to retrieve the specific trouble code and perform thorough testing on the control module temperature sensor circuit.
  2. Inspect Wiring and Connectors: Check the wiring harness and connectors for any signs of damage, corrosion, or loose connections. Repair or replace as needed.
  3. Test Temperature Sensor: Test the temperature sensor to ensure it is functioning correctly. Replace if necessary.
  4. Check Control Module: Verify the operation of the control module and replace if it is found to be faulty.
  5. Clear Codes and Test Drive: Clear the diagnostic trouble codes from the vehicle's memory, and test drive the vehicle to ensure the issue has been resolved.

Cost to Fix P0668 Buick

The cost of repairing a P0668 Buick code can vary depending on the specific cause of the issue and the labor rates in your area. Typically, the cost of replacing a temperature sensor can range from $100 to $200, while addressing wiring or connector issues may add additional labor costs. In total, you can expect to pay between $200 and $400 for parts and labor at an auto repair shop. It's important to keep in mind that these are rough estimates, and actual repair costs may vary based on your location and the specific requirements of your vehicle. Be sure to consult with a qualified mechanic for a more accurate cost 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 P0668 Buick Code

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

P0668 indicates a low voltage issue in the Control Module Temperature Sensor Circuit, which monitors the temperature of the control module to ensure proper operation.

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

Symptoms may include poor engine performance, difficulty starting, erratic idling, reduced fuel efficiency, or the Check Engine Light being illuminated.

3. What causes the P0668 code to appear on a Buick?

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

4. Is it safe to drive a Buick with code P0668?

Driving with this code may increase the risk of engine damage if the control module overheats, so it’s best to address the issue as soon as possible.

5. How can I diagnose the P0668 code on my Buick?

Start by inspecting the sensor wiring and connectors for damage, testing the temperature sensor for proper operation, and using a multimeter to check for voltage issues in the circuit.

6. How do I fix the P0668 code on a Buick?

Repairs may involve replacing the control module temperature sensor, repairing or replacing damaged wiring, or reprogramming/replacing the PCM if necessary.

7. Can a bad control module temperature sensor cause other problems in my Buick?

Yes, a faulty sensor can lead to improper control module operation, affecting engine performance and potentially causing additional fault codes.

8. What tools are needed to fix code P0668 on a Buick?

Tools may include an OBDII scanner, a multimeter, basic hand tools, and possibly a wiring diagram for your vehicle.

9. How much does it cost to fix the P0668 code on a Buick?

The repair cost can vary, with sensor replacement typically ranging from $50 to $200, while PCM replacement or reprogramming could cost $500 or more.

10. Can I clear the P0668 code on my Buick without fixing it?

Clearing the code with an OBDII scanner will turn off the Check Engine Light temporarily, but the issue will likely recur unless the underlying problem is resolved.

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