Troubleshooting E1 error code

E1- An error code caused by a communication problem between indoor and outdoor boards

  • Wiring problem
  • Internal, external issue 
  • Short-circuited component 

 

  • Power off system, restart after 2 min. If code still appears check wiring between the indoor and outdoor board, all wires should be the same color from the outdoor to the indoor
  • Check power coming into the unit at L1 L2, depending on system, should read 115v or 230v if it does not read, problem is at the source of power
  • If error code disappears issue is solved

 

  • With a multimeter set to DC volts the voltage should be checked at the outdoor board between 2, and 3. In some models (L2, S) (RED lead to 2 and BLACK lead to 3) 
  • Voltage should fluctuate from negative 50 to positive 50 meaning the boards are communicating fine
  • If voltage fluctuates with a positive value, the outdoor board has a malfunction 
  • If voltage fluctuates with a negative value, the indoor board has a malfunction 

 

  • If there is a condensation pump, assure pump is not wired at terminal 3or S (some models)
  • Check the Reactor at the outdoor unit.   
    • Check the resistance across the reactor.  The resistance should be 0 Ohms

 

Other causes for an E1

  • Any wire that is solid or not 14 AWG stranded
  • Wire that are spliced
  • Shorted out IDU motor
    • Check the indoor fan to see if the values are reading correctly
  • Shorted out outdoor fan motor
    • Check the outdoor fan to see if the values are reading correctly
  • Check the outdoor fan to see if the values are reading correctly
  • Add magnetic ring around communication wire.
  • Make sure the home is properly grounded or add grounding rod at condensing unit.
  • Was there a new appliance added to the same circuit as the air conditioner

 

 

 

Shorted IDU

 

  • Locate the fan blower and spin with your hand, blower should spin freely
  • If blower does not spin freely, check for any debris that may be blocking the blower
  • If no debris, and fan is hard to spin, suspect broken windings from inside of motor
  • Locate IDU connector and disconnect from the board
  • Check pins for any resistance between the wire, if resistance is found, replace the IDU motor and indoor board

 

  • When checking for a shorted outdoor fan motor
    • Locate the outdoor fan and connector, unplug the fan from board and check with a multi-meter for ohms, should all read O.L, if resistance is found replace outdoor fan and outdoor board

 

Shorted ODU

 

  • Locate the fan blower and spin with your hand, blower should spin freely
  • If blower does not spin freely, check for any debris that may be blocking the blower
  • If no debris, and fan is hard to spin, suspect broken windings from inside of motor
  • Locate ODU connector and disconnect from the board
  • Check pins for any resistance between the wire, if resistance is found, replace the ODU motor and indoor board

 

  • When checking for a shorted outdoor fan motor
    • Locate the outdoor fan and connector, unplug the fan from board and check with a multi-meter for ohms, should all read O.L, if resistance is found replace outdoor fan and outdoor board