The Engine Fault Code P0668 generally refers to a problem with the PCM (Powertrain Control Module), ECM (Engine Control Module), or TCM (Transmission Control Module) related to the internal temperature sensor circuit. This code indicates that the temperature sensor is reading a lower voltage than expected, which may suggest a fault in the sensor or the circuit itself.
While P0668 is fairly standard across many manufacturers, the specific implications can vary depending on the vehicle brand and model. Here are some alternative meanings or related issues for different manufacturers:
1. Porsche: Typically indicates a fault in the PCMs internal temperature sensing circuit, which can affect engine performance and efficiency.
2. Mini: Similar to Porsche, it may indicate an internal fault with the engine control module, potentially leading to poor fuel economy or drivability issues.
3. Mercedes: This code can point to issues with the transmission control module as well, possibly affecting shifting behavior and transmission performance.
4. Audi: Often relates to the engine management system and can trigger other codes if the internal temperature sensor is malfunctioning, impacting overall performance.
5. Jaguar: May indicate a problem with the engine or transmission control systems, leading to warning lights on the dashboard and potential performance issues.
6. Land Rover: Similar to Jaguar, it can indicate issues with the engine or transmission management, possibly resulting in reduced power or efficiency.
In all cases, if you encounter this code, its advisable to check the wiring and connections to the sensor, inspect the sensor itself, and possibly run a diagnostic test to pinpoint the exact issue. Ignoring this code can lead to further complications, so addressing it promptly is important.
The Engine Fault Code P0668 typically indicates an issue with the internal temperature sensor circuit of the Powertrain Control Module (PCM), Engine Control Module (ECM), or Transmission Control Module (TCM). This code can occur for several reasons, and while the general cause is similar across different manufacturers, there can be specific differences based on the make and model of the vehicle. Here are some common causes:
1. Faulty Temperature Sensor: The internal temperature sensor itself may be malfunctioning, leading to inaccurate readings.
2. Wiring Issues: Damaged, corroded, or shorted wiring connected to the sensor can cause low voltage signals, triggering the code.
3. Poor Connections: Loose or corroded connectors can disrupt the signal, leading to a low reading.
4. PCM/ECM/TCM Malfunction: The control module itself might have a fault, causing it to misread the internal temperature.
5. Software Issues: Some manufacturers may have software glitches that can lead to incorrect readings. Updating the software may resolve the issue.
6. Environmental Factors: Extreme temperatures or moisture can affect the sensor`s performance.
Manufacturer-Specific Considerations
– Porsche: These models may have more complex electronic systems. Check for updates or recalls related to the PCM.
– Mini: Wiring issues are common due to the compact design. Inspect wiring harnesses closely.
– Mercedes: Look for specific bulletins on the model in question; they may have known issues with the temperature sensor.
– Audi: Audi vehicles often have intricate electrical systems, so ensure all connectors are secure and free from corrosion.
– Jaguar: Similar to Audi, check for software updates and ensure the wiring is in good condition.
– Land Rover: These vehicles can have issues with moisture intrusion, so inspect the connectors and wiring for water damage.
If you encounter this code, its a good idea to perform a thorough inspection of the wiring and connectors first. If everything looks good, you may want to test or replace the temperature sensor or check for any software updates from the manufacturer.
The P0668 code indicates a problem with the PCM (Powertrain Control Module), ECM (Engine Control Module), or TCM (Transmission Control Module) internal temperature sensor circuit. This can happen in various European cars like Porsche, Mini, Mercedes, Audi, Jaguar, and Land Rover. Heres how to troubleshoot and fix this issue:
Steps to Fix P0668 Code:
1. Check for Other Codes:
– Use an OBD-II scanner to see if there are any other trouble codes. Fixing related codes may help resolve the P0668.
2. Inspect Wiring and Connectors:
– Look for damaged wires or loose connections in the PCM/ECM/TCM circuits. Pay attention to corrosion or frayed wires.
3. Test the Temperature Sensor:
– If your vehicle has a separate temperature sensor, test its resistance with a multimeter. Compare the readings to the specifications in your service manual.
4. Check the PCM/ECM/TCM:
– If the wiring and sensor are fine, the issue may be with the PCM/ECM/TCM itself. A professional diagnostic tool can help check if the module is functioning correctly.
5. Update or Reflash the PCM/ECM/TCM:
– Sometimes, a software update can fix internal sensor issues. Check with the manufacturer for updates.
6. Replace the PCM/ECM/TCM:
– If all else fails and the module is faulty, replacing it might be necessary. This is a more complex fix and may require programming.
Manufacturer-Specific Considerations:
– Porsche: Check the specific wiring diagrams for your model. Some Porsches have unique connectors that may need special attention.
– Mini: Mini vehicles often have complex electrical systems. Ensure that all ground connections are secure.
– Mercedes: Mercedes may require specific diagnostic tools to access deeper module functions. Consider using a Star Diagnostic tool for accurate readings.
– Audi: Audis can have multiple control modules. Make sure to check the communication between them.
– Jaguar: Jaguars sometimes have software issues. If the problem persists, consider a dealer visit for a software reflash.
– Land Rover: Land Rovers may have unique issues with their air suspension and electronic systems. Ensure that all related systems are functioning properly.
Final Notes:
Always refer to the service manual for your specific vehicle model for precise procedures and specifications. If youre unsure or uncomfortable with any steps, its best to consult a professional mechanic.
Driving with a P0668 code, which indicates a low reading from the PCM/ECM/TCM internal temperature sensor circuit, can be concerning. This code typically means there`s an issue with the engine control module`s ability to monitor its own temperature. Heres a breakdown of what you should consider:
General Considerations:
1. Engine Performance: The vehicle may experience poor performance, such as rough idling or stalling, because the engine control unit relies on accurate temperature readings to make adjustments.
2. Fuel Efficiency: You might see a drop in fuel efficiency if the engine isn`t running optimally due to this sensor issue.
3. Potential Damage: If the PCM gets too hot and the system cant regulate it, theres a risk of further damage to the engine or transmission.
Manufacturer Differences:
– Porsche: Generally, it`s not advisable to drive. The performance loss could be significant, and overheating could lead to serious engine damage.
– Mini: Similar to Porsche, driving might be safe for short distances, but its best to get it checked soon to avoid issues.
– Mercedes: Mercedes vehicles have advanced systems that may go into limp mode if they detect a problem. It`s safer to avoid driving until you fix the issue.
– Audi: Audi vehicles may handle the situation similarly to Mercedes. If you notice performance issues, it`s best not to drive.
– Jaguar: Driving might be risky, as Jaguars can have complex electronic systems. It`s better to have it diagnosed quickly.
– Land Rover: These vehicles can also be affected significantly by sensor issues, and its advisable to avoid driving until repaired.
While it might be possible to drive a short distance with a P0668 code, its generally not safe or advisable. The best course of action is to have the vehicle diagnosed and repaired as soon as possible to prevent further damage and ensure safe operation.
