The short answer
Carrier ductless mini split codes in Northern Virginia show up two ways: as a code like E1 or EC on the indoor unit’s display, or as a number of flashes on the operation light when the unit has no display. On Carrier’s 40MAQ indoor units, E1 is lost communication between the indoor and outdoor units, E4 and E5 are temperature sensors, EC is refrigerant leak detection, and P codes like P0 and P1 come from the outdoor unit’s power side. Carrier’s first step: power off, wait, power back on, and see if the code returns.
Find your model first
Codes differ between Carrier’s ductless lines, so check the label on the side of the indoor unit. The codes here are for the 40MAQ and 40MAHB indoor units, two of Carrier’s common wall-mounted lines. If yours is a different line, the meaning of a code can change, and the manual for that model number is the one to trust.
Free Furnace With a New AC
Put in a new AC with its matching coil and a basic single-stage gas furnace goes in with it, installed together. See the free furnace
Want your own number before anyone comes out? The HVAC estimator prices your house in a few questions.
40MAQ indoor codes
With the timer light off, count the flashes on the operation light:
Swipe to see all columns →
Swipe to see all columns →
| Code | Flashes | What it means |
|---|---|---|
| E0 | 1 | Indoor unit memory (EEPROM) fault |
| E1 | 2 | Indoor and outdoor units can’t communicate |
| E2 | 3 | Zero-crossing signal fault (power sensing) |
| E3 | 4 | Indoor fan speed out of range |
| E4 | 5 | Room temperature sensor (T1) |
| E5 | 6 | Indoor coil temperature sensor (T2) |
| EC | 7 | Refrigerant leak detected |
With the timer light on, the flashes point outside: F1 (2 flashes) the outdoor air sensor, F2 (3) the condenser coil sensor, F3 (4) the discharge sensor, F4 (5) the outdoor unit memory, and F5 (6) the outdoor fan. P codes are power and compressor faults: P0 an overcurrent in the inverter module, P1 high or low voltage, P2 compressor overheating, and P4 the inverter drive.
40MAHB codes
Swipe to see all columns →
Swipe to see all columns →
| Code | What it means |
|---|---|
| EH 00 or EH 0A | Indoor memory (EEPROM) |
| EL 01 | Indoor and outdoor communication |
| EH 02 | Zero-crossing signal |
| EH 03 | Indoor fan speed |
| EH 60, EH 61 | Room sensor (T1), indoor coil sensor (T2) |
| EH 0b | Indoor board and display can’t communicate |
| EL 0C | Refrigerant leak detected |
| EC 51 to EC 56 | Outdoor memory and sensors |
| EC 07 | Outdoor fan speed |
| PC 00 to PC 04 | Inverter module, voltage, compressor overheating or pressure, inverter drive |
| PC 08 | Current overload |
| PC 40 | Communication between the outdoor main chip and the compressor drive chip |
When it isn’t a fault: defrost
In heating mode, a mini split stops its fans for a few minutes to melt frost off the outdoor coil, and Carrier’s owner’s manual says a DEFROST indicator lights while it does. If the indoor unit goes quiet on a cold morning with that light on, give it a few minutes. Our heat pump covered in ice guide explains what’s normal outside.
What you can safely check
- Turn the system off at the breaker or the disconnect, wait a few minutes, and turn it back on. If the code doesn’t come back, write down which one it was.
- Clean the indoor unit’s filters. Clogged filters choke the indoor coil.
- Clear snow, leaves or anything stacked around the outdoor unit.
- For E1 or EL 01, look at whether anything happened to the line set or the wire between the units: new siding, a deck project, a critter.
What a technician does
For communication codes we check the wiring between the units and the voltage at each end. Sensor codes mean reading the sensor’s resistance against its chart. An EC or EL 0C leak code means a leak search before anyone adds refrigerant, because a recharge without a fix leaks out again. P codes get the inverter board and compressor tested.
A repair visit starts with a flat $99 diagnostic, and you get the price of the fix before we touch anything. Our Carrier repair page lists what the common repairs cost. Our ductless mini split page covers repair and new systems. Our heating check is $67 per system, through December 31: furnace, heat pump or boiler.
Related: Carrier heat pump codes, heat pump covered in ice and, for the furnace side, our full list of Carrier furnace codes.
Every code meaning here comes from Carrier’s own documents: 40MAQ service manual, 40MAHB service guide and ductless owner’s manual.
Call or book
Call (703) 997-9757 and tell us the code you counted, or book online from goswiftpro.com/cookiesoffer and a box of warm cookies comes with the visit. Rated 5.0 stars across 1,138 reviews on Google, Angi, Yelp, the BBB and Facebook, Virginia Class A license 2705192276.
Questions people ask
What does E1 mean on a Carrier mini split?
On Carrier’s 40MAQ units, E1 means the indoor and outdoor units can’t communicate. It flashes twice on units without a display. Check the breaker first, then call.
What does EC mean on a Carrier mini split?
On the 40MAQ, EC is refrigerant leak detection. It needs a leak search, not just a recharge.
How do I reset a Carrier mini split error code?
Turn the power off at the breaker or disconnect, wait a few minutes, and turn it back on. If the code comes back, it’s a real fault.
Why did my Carrier mini split stop blowing in cold weather?
It’s likely defrosting. The fans stop for a few minutes and a DEFROST indicator lights while it melts frost off the outdoor coil.
