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Engine-Codes – Generic – P0668

P0668 Code - Control Module Temperature Sensor Circuit Low Voltage

Quick Answer

The diagnostic trouble code P0668 refers to the Control Module Temperature Sensor Circuit Low Voltage. Common causes include Faulty temperature sensor, Damaged wiring or connectors in the sensor circuit, Corrosion or debris affecting sensor operation. 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 indicates Control Module Temperature Sensor Circuit Low Voltage.
Common causes
Common causes include Faulty temperature sensor, Damaged wiring or connectors in the sensor circuit, Corrosion or debris affecting sensor operation.
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 10, 2024
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Code P0668 Description

The diagnostic trouble code P0668 refers to the Control Module Temperature Sensor Circuit Low Voltage. This code indicates that the powertrain control module (PCM) has detected a lower than expected voltage from the temperature sensor circuit. The temperature sensor is responsible for monitoring the temperature of the control module, ensuring that it operates within the optimal temperature range. When the voltage is too low, it can lead to issues with the control module's performance and potentially cause damage if left unaddressed.

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

Common Causes of P0668

  1. Faulty temperature sensor
  2. Damaged wiring or connectors in the sensor circuit
  3. Corrosion or debris affecting sensor operation
  4. Issues with the control module

Symptoms of P0668

  1. Check Engine Light illuminated
  2. Poor engine performance
  3. Decreased fuel efficiency
  4. Stalling or hesitation during acceleration
  5. Rough idling

How to Fix P0668

  1. Perform a thorough inspection of the temperature sensor circuit, including wiring and connectors, to identify any visible damage or corrosion.
  2. Test the temperature sensor's resistance and voltage output to determine if it is functioning correctly.
  3. Replace the temperature sensor if it is found to be faulty or not providing accurate readings.
  4. Clear the diagnostic trouble codes from the PCM and perform a test drive to ensure the issue has been resolved.
  5. If the problem persists, further diagnostic testing may be necessary to identify any underlying issues with the control module.

Cost to Fix P0668

The typical repair costs for addressing the P0668 code can vary depending on the specific cause of the issue. In general, replacing a faulty temperature sensor can cost anywhere from $50 to $200, including parts and labor. Additional costs may be incurred if wiring or connectors need to be repaired or replaced. It is advisable to consult with a professional mechanic or auto repair shop to obtain a more accurate estimate based on the specific circumstances of the vehicle. Keep in mind that labor rates can vary between different locations and service providers.

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Code P0668 Information for Specific Makes

  • P0668 BMW — DME Internal Fault Interior Temperature Sensor Signal
  • P0668 Buick — Control Module Temperature Sensor Circuit Low Voltage
  • P0668 Cadillac — Control Module Temperature Sensor Circuit Low Voltage
  • P0668 Chevrolet — Control Module Temperature Sensor Circuit Low Voltage
  • P0668 GMC — Control Module Temperature Sensor Circuit Low Voltage
  • P0668 Mazda — ECM/TCM Internal Temperature Sensor Circuit Low
  • P0668 MINI — DME Internal Fault Interior Temperature Sensor Signal
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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