P1D21 – BMW DTC

BMW DTC P1D21 – Electric A/C Compressor Control Module Internal Temperature Sensor ‘B’ Temperature Out of Range Low

DTC P1D21 meaning on BMW

DTC P1D21 on a BMW indicates an issue with the Electric A/C Compressor Control Module Internal Temperature Sensor ‘B’. Specifically, it means that the temperature reading from sensor ‘B’ is out of range on the low end.

BMW DTC P1D21 symptoms

Symptoms of DTC P1D21 on a BMW may include:

  • Malfunctioning air conditioning system
  • Reduced cooling performance
  • Dashboard warning light related to the A/C system

BMW DTC P1D21 causes

Common causes of DTC P1D21 on a BMW include:

  • Failed Electric A/C Compressor Control Module
  • Wiring or connection issues with the temperature sensor ‘B’
  • Internal fault within the temperature sensor ‘B’

BMW DTC P1D21 seriousness

The seriousness of DTC P1D21 on a BMW depends on the driving conditions and climate. While it may not directly affect the drivability of the vehicle, a malfunctioning A/C system can be uncomfortable, especially in hot weather.

How to diagnose DTC P1D21 on BMW

To diagnose DTC P1D21 on a BMW, a mechanic would typically:

  • Use a diagnostic scanner to retrieve the fault codes
  • Inspect the Electric A/C Compressor Control Module and its connections
  • Test the temperature sensor ‘B’ for proper operation

How to fix DTC P1D21 on BMW

To fix DTC P1D21 on a BMW, the following steps may be taken:

  • Replace the Electric A/C Compressor Control Module if faulty
  • Repair any wiring or connection issues related to temperature sensor ‘B’
  • Replace the temperature sensor ‘B’ if it is internally faulty

How to erase DTC P1D21 on BMW

To erase DTC P1D21 on a BMW, the fault codes can be cleared using a diagnostic scanner. Once the underlying issue has been addressed and fixed, the codes can be cleared to reset the system and turn off the warning light.