I noticed that the air conditioning works worse in automatic mode than before. The refrigerant level is fine. It works better in manual mode, but in the past, the automatic mode was always sufficient for me. I found the OBD code L0164 Lost Communication With HVAC Control Module, so I guess I was right, and there is indeed a malfunction. What should be replaced to fix this error? MY2011 TD4 S Manual
MY2014 Si4 HSE Auto
MY2017 C63S Coupe

Could be worth trying a second hand module. Be sure to replace the existing one with a similar code, its on a paper label at the back of the module. That's what I would try first.

I think the Code was U0164, it suggests that the car main systems are not able to talk reliably to the HVAC Module, which may not be the fault of that unit.

Before swapping out unit I suggest that you ---

Remove the Battery Leads and do a Hard Reset

Clear any remaining OBD Codes in system

Disconnect, Clean, and Reconnect Connections to HVAC Module

Check for any visible Damaged Cabling in that area

If you have other Lost Comms Failure Codes from other Modules, you will need to check the integrity of the MS CAN Network. (Page 3017 Repair and Wiring Manual)

From the Repair Manual
U0164-00 - Lost Communication with HVAC Control Module

Lost communication with climate control module
-Carry out the associated network test for this DTC using the manufacturer approved diagnostic system

PS Have you unplugged or disturbed any other module that may be on the same comms network lately? FL2 XS SD4 Auto 2010 2012-2017 (21k - 91k miles) (MY2011)
FL2 Metropolis SD4 Auto 2014 2017- (16k - 82k+ miles) (MY2015)
Metro in its 11th Year of (Extended) LR Warranty / Full LR Service History
(Expensive, but Trouble/Worry free - hopefully?)

I have a mystery. I bought this air conditioning button module panel on eBay. It is not easy to find A/C buttons panel with 100% identical part numer located on backside label. It's hard to say what the numbers stand for, where the version of the equipment is and where its revision or factory is.

Anyway, my air conditioning is working again as if the car were new, the full heating power has returned. However, after errors reset, the new OBD errors U0164 are back. It's a strange thing. Probably not related to each other.

BTW. If I had bought such a used car, I would never have thought that the air conditioning performance could be better. MY2011 TD4 S Manual
MY2014 Si4 HSE Auto
MY2017 C63S Coupe

Last edited by pporocki on 30th Mar 2025 9:33 pm. Edited 1 time in total

I took apart this broken air conditioning module, thinking I’d find some burnt components or swollen capacitors, but visually everything seems fine at first glance. The board shows signs of manual fixes with rosin (it must have been done at the factory because I never reported any issues with the AC during the warranty period, and no car service would do that; they would replace it with a new one from the manufacturer). The AC controller module is made by "ALPS Czech," probably the same well-known company that makes potentiometers, as the potentiometers also have ALPS written on them. The integrated circuits are coated with some transparent blue substance, probably to protect them from moisture. To properly check the capacitors, I'd need to desolder them, but I don’t feel like doing that anymore. The plastic casing makes a lot of cracking noises, and I looked into whether I could dampen the noise with Tessa fabric tape, but the outlook isn’t promising.

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The module is a cheap part from a scrappy at least in the UK, There are a few different ones, six I think but don't hold me to that