Carrier bryant Multi-Zone 38MARBQ09 18AA3 Series Service Manual page 9

All Models
Indoor Outdoor Unit Communication Error E1 (page 3 of 3)
Check the wiring connection from outdoor terminal to outdoor
PCB and wiring between PCB's if there is more than 1 PCB
For ODU's with 2 PCB's,
main and IPM (Inverter).
Check the AC voltage of L, N
output to IPM board. Is it the
same as the power input?
Yes
Unplug all the high voltage
components connected to main
PCB (4 way valve, heater(s), fan)
one by one to check their
resistance. Has any component
short circuited or open?
No
Unplug the electronic expansion
valve. Repower ODU, Check if
the power LED is on.
No
Replace the IPM board.
Replace the electronic expansion
valve coil & Main PCB
For some models, outdoor PCB cannot be removed separately. In
these cases, the entire outdoor electric control box should be
replaced as a whole. Parts breakdown shows this information.
No
Replace the main PCB
Replace short
circuited
Yes
component and
main PCB.
Replace the short
circuited component
and the main PCB.
Yes
For ODU's with only 1 PCB
Check that the
power LED is on.
No
Unplug all the high voltage
components connected to the
main PCB (4-way valve, heater,
AC fan) one by one to check
their resistance. Has any
component short circuit?
Yes
Unplug the electronic expansion
valve. Repower ODU, Check if
the power LED is on.
Yes
Replace the main PCB
If after parts
replacement, E1 is still
displayed, contact your
local CE Technical
Support Rep.
No
No