P1620 – BMW DTC

BMW DTC P1620 – Map Cooling Thermostat Control Circuit High

DTC P1620 meaning on BMW

The Diagnostic Trouble Code (DTC) P1620 for BMW refers to an issue with the Map Cooling Thermostat Control Circuit being detected as high. This means that the engine control module (ECM) has detected a high voltage signal from the map cooling thermostat control circuit, indicating a potential problem with the thermostat control system.

BMW DTC P1620 symptoms

Symptoms of DTC P1620 on a BMW may include:

• Check Engine Light (CEL) illuminated on the dashboard
• Engine overheating or running hotter than normal
• Reduced engine performance or efficiency

BMW DTC P1620 causes

Common causes of DTC P1620 on a BMW include:

• Faulty map cooling thermostat
• Wiring or connector issues in the thermostat control circuit
• ECM software or hardware problems

BMW DTC P1620 seriousness

While DTC P1620 may not always result in immediate drivability issues, it is important to address this code promptly to prevent potential engine damage or overheating. Ignoring this code could lead to more severe problems over time.

How to diagnose DTC P1620 on BMW

To diagnose DTC P1620 on a BMW, you can follow these steps:

1. Use a diagnostic scanner to retrieve the fault codes stored in the ECM
2. Inspect the map cooling thermostat and its wiring for any visible damage or corrosion
3. Test the thermostat control circuit for proper voltage and continuity
4. Check for any software updates available for the ECM

How to fix DTC P1620 on BMW

To fix DTC P1620 on a BMW, you may need to:

1. Replace the faulty map cooling thermostat
2. Repair any damaged wiring or connectors in the thermostat control circuit
3. Clear the fault codes using a diagnostic scanner after the repairs
4. Perform a test drive to ensure the issue has been resolved

How to erase DTC P1620 on BMW

To erase DTC P1620 on a BMW, you can:

1. Use a diagnostic scanner to access the ECM and clear the fault codes
2. Follow the on-screen prompts to erase the DTC P1620 code
3. Ensure that the issue causing the fault code has been resolved before clearing it

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

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