P0666 – BMW DTC

BMW DTC P0666 – Control Module Internal Temperature Sensor ‘A’ Circuit

DTC P0666 meaning on BMW

DTC P0666 for BMW refers to the Control Module Internal Temperature Sensor ‘A’ Circuit. This diagnostic trouble code indicates that there is a malfunction in the internal temperature sensor circuit of the control module.

BMW DTC P0666 symptoms

Symptoms of BMW DTC P0666 may include:

• Check Engine Light illuminated on the dashboard
• Engine running rough or misfiring
• Reduced engine performance
• Potential overheating issues

BMW DTC P0666 causes

Common causes of BMW DTC P0666 include:

• Faulty internal temperature sensor
• Wiring or connection issues in the sensor circuit
• Defective control module

BMW DTC P0666 seriousness

While DTC P0666 may not always result in immediate drivability issues, it is important to address this code promptly to prevent potential damage to the engine or control module.

How to diagnose DTC P0666 on BMW

To diagnose DTC P0666 on a BMW, you can follow these steps:

1. Use a diagnostic scanner to retrieve the fault codes stored in the vehicle’s computer.
2. Inspect the internal temperature sensor and its wiring for any visible damage or corrosion.
3. Test the sensor’s resistance and voltage to determine if it is functioning correctly.
4. Check the control module for any signs of malfunction.

How to fix DTC P0666 on BMW

To fix DTC P0666 on a BMW, you may need to:

1. Replace the internal temperature sensor if it is found to be faulty.
2. Repair any damaged wiring or connections in the sensor circuit.
3. If the control module is defective, it may need to be replaced or reprogrammed.

How to erase DTC P0666 on BMW

To erase DTC P0666 on a BMW, you can:

1. Use a diagnostic scanner to clear the fault codes stored in the vehicle’s computer.
2. After making the necessary repairs, drive the vehicle to see if the code returns.
3. If the issue has been resolved, the Check Engine Light should turn off on its own.

Recommended tools & DTC Scanners for BMW

Best Diagnostic App for modern BMWs: BimmerLink

Recommended Bluetooth adapter for Bimmerlink: OBDLink CX

Cable adapter for Bimmerlink: Enet Cable USB Type C

For older BMWs we recommend: Autel AutoLink AL319 (2024 version)

Easy-to-use Multimeter for reliable diagnostics: AstroAI Auto-ranging Multimeter

Some of the links on this page may be affiliate links, which means we may earn a small commission if you make a purchase. This helps us keep our DTC database up to date and provide valuable content for free. We only recommend products that we have tested and believe to be the best in their class.