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PC40 Main chip to compressor drive chip communication error

High severity Midea DLCM(R/H)B multi-zone outdoorMidea DLFSHBH wall indoor (DLCM multi-zone)

What the control is telling you

The outdoor main chip gets no reply from the compressor drive (IPM) side for 60 s. Outdoor board shows E3; 48K HH shows J4.

Applies to: DLCM(R/H)B multi-zone outdoor units with DLFSHBH high wall indoor units (Midea, Carrier, Viessmann)

Likely causes

  • Loose signal cable
  • Bad IPM board
  • Bad outdoor main board

Test and repair steps

  1. Safety kill power at the disconnect and wait for the inverter capacitors to discharge before touching boards or wiring.
  2. With power on, check that at least one LED on the IPM board is lit.
  3. Check the signal cable between the IPM and main board. At the plug: black to white about 5 V DC, black to red about 12 V DC.
  4. Reseat the cable and retry.
  5. Still faulty replace the IPM board, then the outdoor main board, then the whole electric control box.

Models that show this code

12 models in Midea DLCM(R/H)B multi-zone outdoor, Midea DLFSHBH wall indoor (DLCM multi-zone)

DLCMHBH24CAKDLCMHBH30DAKDLCMHBH36DAKDLCMHBH48EAKDLCMRBH18BAKDLCMRBH36DAKDLCMRBH48EAKDLFSHBH09XAKDLFSHBH12XAJDLFSHBH12XAKDLFSHBH18XAKDLFSHBH24XAK

Other codes on the same units

  • PC11 AC supply voltage protection (over voltage)
  • PC12 DC bus high voltage / 341 MCE error
  • PC30 High pressure protection
  • PC31 Low pressure protection
  • PC41 Current input detection protection
  • PC42 Compressor start failure
  • PC43 Compressor phase loss
  • PC44 Zero speed protection

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Source: DLCMRBH/DLCMHBH Multi-Zone Outdoor Service Manual (sold as Midea, Carrier and Viessmann Vitocal 200-S; Viessmann doc 6225551-03, 12/2024), Table 23 Outdoor Unit Error Display p.26; diagnosis p.49-50; Carrier MS-DLFSHB-01 High Wall Ductless Service Manual (04/2021), Table 9 p.17, p.38. Summarized in our own words; check the original manual for your model.

Homeowner looking at this code? See what it means for you and when to call a technician.

For licensed technicians. Gas, electrical and refrigerant work must be done by a qualified, licensed person. Shut off power and gas before servicing, never bypass a safety control, and follow the manufacturer’s manual for the exact model; it and local codes always take priority. HVACopedia is not affiliated with any manufacturer; brand and model names only identify the equipment.