What is OBD-II Code P0668 – Control Module Internal Temperature Sensor A Circuit Low
If you are an average person who may not have a lot of technical knowledge about cars but encountered OBD-II Code P0668 in your car, fret not. In this article, we will explain what this code means, how to repair the issue, and provide additional information to help you understand the issue better.
What is OBD-II Code P0668?
The OBD-II (On-board Diagnostics) system is a standardized system that monitors your car’s performance and emissions. P0668 is a diagnostic trouble code (DTC) that relates to the control module internal temperature sensor A circuit. The powertrain control module (PCM) monitors the internal temperature of the control module to ensure that it is within the acceptable range. If the internal temperature of the control module falls below the acceptable range, it will trigger the P0668 code.
The control module internal temperature sensor monitors the temperature of the control module, which houses the engine computer, transmission control module, and other electronic modules. The control module operates at a specific temperature range to ensure that it functions properly. If the internal temperature sensor detects that the control module has a low temperature, it will trigger the P0668 code, indicating a problem with the A circuit.
What are the symptoms of P0668?
The symptoms of P0668 code include:
1. Check Engine Light: The most obvious symptom of P0668 code is a Check Engine Light (CEL) on the instrument cluster. The CEL will illuminate to warn you that there is a problem with your car.
2. Harsh shifting: P0668 code can cause your car to shift gears harshly or erratically.
3. Poor fuel economy: A fault in the A circuit can lead to poor fuel economy. Your car may require more fuel to run at the same rate, resulting in increased fuel consumption.
4. Stalling: P0668 code can cause your car to stall when you come to a stop. The engine may struggle to start again, and you may need to pump the gas pedal to restart it.
What causes P0668 code?
The most common causes of P0668 code are:
1. Faulty internal temperature sensor: The internal temperature sensor may be faulty or have a low signal output, triggering the P0668 code.
2. Wiring issues: The wiring connected to the internal temperature sensor may be faulty or broken, causing the sensor to give a low reading and triggering the code.
3. Failed control module: If the control module is not functioning correctly or is damaged, it may cause the temperature sensor to give inaccurate readings.
How to diagnose P0668 code?
Before diagnosing the P0668 code, you will need a diagnostic tool that can read the codes for your car. Once you have the tool, follow these steps:
1. Clear the code: Clear any stored codes, start the engine, and let the car run for a while.
2. Check the wiring: Use a voltmeter to check the wiring that connects the internal temperature sensor to the control module. Inspect the wiring to ensure that there are no cracks or breaks.
3. Internal Temperature Sensor Test: Check the internal temperature sensor for resistance. Check the resistance of the sensor with a multimeter. If the resistance is out of range, replace the temperature sensor.
4. Control Module Test: If the internal temperature sensor tests are within tolerance, then the control module may need inspection. Check any wiring or connections to the ECU that may be disconnected or damaged. After that, follow appropriate troubleshooting steps to repair or replace the control module.
How to repair P0668 code?
Once you have diagnosed the issue, it’s time to repair the P0668 code. Here are some of the repairs you can try:
1. Replace the Internal Temperature Sensor: If the internal temperature sensor is faulty, then replace it with a new one. This will ensure that the sensor is giving accurate readings to the control module.
2. Repair the wiring: Once you have identified the broken wire, replace it using a soldering iron or crimp the wire connectors together.
3. Replace the Control Module: If the control module is not functioning correctly or is damaged, then replace it with a new one.
3. Continue driving: If the code clears, drive the car for a while to ensure that the code does not come back. If it does, repeat the above steps.
Frequently Asked Questions:
1. Can I still drive my car if it has P0668 code?
Ans: It’s not advisable to continue driving your car if it has P0668 code. The underlying issue needs to be resolved as it can affect your car’s performance, fuel economy, and other parts of the engine.
2. How much does it cost to repair P0668 code?
Ans: The cost of repairing P0668 code depends on the severity of the issue and the parts that need replacement. Generally, it costs between $100 to $500 to fix the issue.
3. Can I fix P0668 code by myself?
Ans: If you have a good knowledge of cars and are comfortable doing electrical work, then you can fix P0668 code yourself. However, it is better to get your car to a certified mechanic if you are not confident in your skills.
4. Can P0668 code cause engine damage?
Ans: P0668 code itself cannot cause engine damage. However, if the underlying issues are not fixed, it can affect other parts of the engine, reducing its efficiency and ultimately causing damage.
5. Will P0668 code clear on its own?
Ans: P0668 code will not clear on its own. You need to diagnose and repair the problem to clear the code.
Conclusion:
If your car has a P0668 code, it’s essential to get it diagnosed and repaired as soon as possible. The code can cause problems with your car’s performance, lead to fuel inefficiency, and potentially cause engine damage. By following the diagnosis and repair steps outlined above, you can reduce the impact of P0668 code and get your car back to running smoothly.
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