Coolant Circulation Pump

Back to: WIS 83.40 Automatic Climate Control (ACC) or Heating Ventilation and Air Conditioning (HVAC)

Description - Coolant Circulation Pump

The Coolant Circulation Pump (A31/m1) is also known as - "Auxiliary Water Pump".

Edit required.

Issues - Coolant Circulation Pump

• It may be hard to notice that your coolant circulation pump (A31/m1) is not working properly.
• If the pump is dead, then in cold weather the car could not be heated more than 30C even if ACC was set to "HI".

Parts - Coolant Circulation Pump

• 0 392 020 066" or 0392020066
• A2208350064

Diagnosis - Coolant Circulation Pump

• Error code: B1416 "The component or the signal line to the component A31m1 (coolant circulation pump) has short circuit to positive or overload."
• Note: error code B1416 is thrown if coolant circulation pump draws >5A current.

Testing - Coolant Circulation Pump

• I removed the pump and connected it to 12V DC. The pump did not spin at all (it was completely stuck and I could not rotate it even by hand) and the multimeter showed that it consumed 5.5A current.

Conclusion:

While you can buy a brand new pump for 140 EUR you might as well try to repair it. The reference shows how you can do it.

DIY Procedures - Coolant Circulation Pump

Repair - Coolant Circulation Pump

Acknowledgement of contribution by BenzWorld Member, Pokseva.

Refer to: http://www.benzworld.org/forums/showthread.php?t=1271866http://www.benzworld.org/forums/w210-e-class/1570724-my-attempt-replacing-transmission-plug.html