Universal AC Error Code
& Diagnostic Directory
Type your error code and get the meaning, likely cause, and exact action in under 3 seconds. Covers Daikin, LG, Voltas, Samsung, Panasonic, Hitachi, Blue Star & Carrier.
69+
Error Codes Indexed
8 Brands
Major Indian AC Brands
12 Patterns
Blink Codes Decoded
6 Resets
Brand Reset Sequences
Jump to Brand
DIY Safe
Clean filters, replace batteries, clear drain, MCB reset. No tools or expertise needed.
Technician Advised
Sensor replacements, PCB issues, motor faults. Requires certified HVAC technician.
DANGER — Stop AC
Refrigerant leaks, compressor faults, high voltage. Stop AC immediately and call a pro.
Instant Error Code Search
Search by code (E1, CH05), brand name, or symptom description
Showing 69 of 69 error codes
Indoor room temperature sensor fault
Likely Cause
NTC sensor open circuit or short circuit
Recommended Action
Replace indoor NTC sensor — ₹300–500. DIY if comfortable with electronics.
Indoor coil temperature sensor fault
Likely Cause
Coil sensor damaged or disconnected
Recommended Action
Replace coil temperature sensor — ₹300–500.
Outdoor temperature sensor fault
Likely Cause
Outdoor NTC sensor failure
Recommended Action
Replace outdoor ambient sensor — ₹300–500.
Indoor/Outdoor communication error
Likely Cause
Loose inter-unit wiring or PCB fault
Recommended Action
Check 3-core communication cable. If intact, PCB replacement needed — ₹2,000–5,000.
Outdoor unit EEPROM error
Likely Cause
Outdoor PCB memory corruption
Recommended Action
Outdoor PCB replacement — ₹3,000–6,000. Call technician.
Outdoor current sensor fault
Likely Cause
Current transformer failure
Recommended Action
Outdoor PCB or current sensor replacement.
DC peak current protection
Likely Cause
Compressor overload or inverter board fault
Recommended Action
Stop AC. Check power supply stability. Call technician.
Outdoor discharge temperature sensor fault
Likely Cause
Discharge pipe sensor failure
Recommended Action
Replace discharge temperature sensor.
Outdoor temperature sensor fault
Likely Cause
Outdoor NTC sensor open/short
Recommended Action
Replace outdoor NTC sensor — ₹300–500.
Outdoor fan motor fault
Likely Cause
Fan motor failure or capacitor fault
Recommended Action
Check outdoor fan capacitor first (₹300). If fan still fails, motor replacement — ₹1,500–3,000.
Indoor PCB fault
Likely Cause
PCB component failure or power surge damage
Recommended Action
Indoor PCB replacement — ₹2,000–5,000. Call Daikin service.
Drain level sensor fault / drain pump error
Likely Cause
Blocked drain or float switch stuck
Recommended Action
Clear drain pipe blockage first. If persists, float switch replacement.
Freeze protection / high pressure protection
Likely Cause
Dirty filter, low refrigerant, or blocked airflow
Recommended Action
Clean filter immediately. If persists, check refrigerant level.
Indoor fan motor fault
Likely Cause
Fan motor failure or capacitor fault
Recommended Action
Fan motor or capacitor replacement — ₹1,500–3,000.
Heat exchanger sensor fault
Likely Cause
Thermistor sensor failure
Recommended Action
Replace thermistor sensor — ₹400–600.
Remote controller sensor fault
Likely Cause
Remote sensor damaged
Recommended Action
Replace remote controller — ₹800–1,500.
Outdoor PCB fault
Likely Cause
Outdoor PCB failure or power surge
Recommended Action
Outdoor PCB replacement — ₹3,000–6,000.
High pressure protection
Likely Cause
Dirty condenser coil, blocked airflow, or overcharge
Recommended Action
Clean outdoor unit coil. Check for airflow obstruction. Call technician.
Low pressure protection
Likely Cause
Refrigerant leak or expansion valve fault
Recommended Action
Stop AC. Refrigerant leak check required — call technician.
Outdoor fan motor fault
Likely Cause
Fan motor failure or capacitor fault
Recommended Action
Fan motor replacement — ₹1,500–3,000.
Expansion valve fault
Likely Cause
Electronic expansion valve failure
Recommended Action
EEV replacement — ₹2,000–4,000. Call Daikin service.
Indoor fan motor fault
Likely Cause
Blower motor failure
Recommended Action
Indoor blower motor replacement — ₹1,500–3,000.
Electrical box temperature high
Likely Cause
Poor ventilation around outdoor unit
Recommended Action
Ensure 30cm clearance around outdoor unit. Clean condenser coil.
Refrigerant shortage
Likely Cause
Refrigerant leak
Recommended Action
Stop AC. Leak detection and gas refill — ₹1,500–3,000.
Indoor/Outdoor communication error
Likely Cause
Wiring fault or PCB issue
Recommended Action
Check inter-unit cable. PCB replacement if wiring is intact.
Indoor ambient sensor open/short
Likely Cause
Room temperature sensor failure
Recommended Action
Replace indoor NTC sensor — ₹300–500.
Indoor coil sensor open/short
Likely Cause
Coil temperature sensor failure
Recommended Action
Replace coil sensor — ₹300–500.
Outdoor coil sensor fault
Likely Cause
Outdoor coil sensor failure
Recommended Action
Replace outdoor coil sensor.
Outdoor ambient sensor fault
Likely Cause
Outdoor temperature sensor failure
Recommended Action
Replace outdoor ambient sensor.
Outdoor discharge sensor fault
Likely Cause
Discharge pipe sensor failure
Recommended Action
Replace discharge sensor.
Communication error
Likely Cause
Wiring fault between indoor and outdoor units
Recommended Action
Check 3-core cable. PCB replacement if wiring intact.
High voltage protection
Likely Cause
Supply voltage above 265V
Recommended Action
Install voltage stabilizer. Check power supply.
Low voltage protection
Likely Cause
Supply voltage below 170V
Recommended Action
Install voltage stabilizer — ₹3,000–5,000.
Compressor discharge temperature high
Likely Cause
Low refrigerant or compressor overload
Recommended Action
Stop AC immediately. Refrigerant check required.
Indoor fan motor fault
Likely Cause
Blower motor failure
Recommended Action
Indoor fan motor replacement — ₹1,500–3,000.
Indoor temperature sensor error
Likely Cause
Room temperature sensor failure
Recommended Action
Replace NTC sensor — ₹400–600.
Indoor coil sensor error
Likely Cause
Coil sensor failure
Recommended Action
Replace coil sensor — ₹400–600.
Outdoor temperature sensor error
Likely Cause
Outdoor sensor failure
Recommended Action
Replace outdoor sensor.
High pressure protection
Likely Cause
Dirty condenser or refrigerant overcharge
Recommended Action
Clean outdoor unit. Check refrigerant pressure.
Low pressure protection
Likely Cause
Refrigerant leak
Recommended Action
Stop AC. Leak detection required.
Communication error
Likely Cause
Inter-unit wiring fault
Recommended Action
Check communication cable. PCB replacement if needed.
Indoor fan motor error
Likely Cause
Blower motor failure
Recommended Action
Indoor fan motor replacement.
Normal operation (no fault)
Likely Cause
No fault present
Recommended Action
No action needed.
Indoor/Outdoor communication error
Likely Cause
Wiring fault or PCB issue
Recommended Action
Check inter-unit cable. PCB replacement if needed.
Capacity setting error
Likely Cause
Mismatch between indoor and outdoor unit
Recommended Action
Verify unit compatibility. Call Panasonic service.
Indoor ambient sensor fault
Likely Cause
Room temperature sensor failure
Recommended Action
Replace indoor NTC sensor.
Outdoor temperature sensor fault
Likely Cause
Outdoor sensor failure
Recommended Action
Replace outdoor sensor.
Indoor coil sensor fault
Likely Cause
Coil sensor failure
Recommended Action
Replace coil temperature sensor.
Outdoor coil sensor fault
Likely Cause
Outdoor coil sensor failure
Recommended Action
Replace outdoor coil sensor.
4-way valve fault
Likely Cause
Reversing valve failure (heat pump models)
Recommended Action
4-way valve replacement — ₹2,000–4,000.
Freeze protection activated
Likely Cause
Dirty filter or low refrigerant
Recommended Action
Clean filter. If persists, check refrigerant.
Outdoor unit protection
Likely Cause
High discharge temperature
Recommended Action
Check outdoor unit ventilation. Call technician.
Indoor PCB error
Likely Cause
PCB component failure
Recommended Action
Indoor PCB replacement — ₹2,000–5,000.
Indoor fan motor error
Likely Cause
Blower motor failure
Recommended Action
Indoor fan motor replacement.
Outdoor unit protection
Likely Cause
High pressure or temperature protection
Recommended Action
Check outdoor unit airflow. Call technician.
Compressor protection
Likely Cause
Compressor overload or fault
Recommended Action
Stop AC immediately. Compressor inspection required.
Outdoor unit communication error
Likely Cause
Inter-unit wiring fault
Recommended Action
Check communication cable between units.
Room temperature sensor fault
Likely Cause
NTC sensor failure
Recommended Action
Replace indoor NTC sensor — ₹300–500.
Coil temperature sensor fault
Likely Cause
Coil sensor failure
Recommended Action
Replace coil sensor.
Outdoor sensor fault
Likely Cause
Outdoor temperature sensor failure
Recommended Action
Replace outdoor sensor.
Communication error
Likely Cause
Wiring fault between units
Recommended Action
Check inter-unit cable. PCB replacement if needed.
High voltage protection
Likely Cause
Supply voltage above safe limit
Recommended Action
Install voltage stabilizer.
Compressor discharge temperature high
Likely Cause
Low refrigerant or compressor fault
Recommended Action
Stop AC. Refrigerant check required.
Indoor temperature sensor fault
Likely Cause
Room sensor failure
Recommended Action
Replace indoor NTC sensor.
Indoor coil sensor fault
Likely Cause
Coil sensor failure
Recommended Action
Replace coil sensor.
Outdoor sensor fault
Likely Cause
Outdoor temperature sensor failure
Recommended Action
Replace outdoor sensor.
Communication error
Likely Cause
Inter-unit wiring fault
Recommended Action
Check communication cable.
High pressure protection
Likely Cause
Dirty condenser or refrigerant overcharge
Recommended Action
Clean outdoor unit. Check refrigerant.
Low pressure protection
Likely Cause
Refrigerant leak
Recommended Action
Stop AC. Leak detection required.
How to Read AC Error Codes: Blinking Lights vs. Digital Displays
Many Indian ACs communicate faults through LED blink patterns — no display needed
Blinking Light Translator
No display? Count the blinks and decode the fault
Select Your Brand
Number of Blinks: 1
LG — 1 Blink
Indoor temperature sensor fault (CH01)
Replace indoor NTC sensor
Hard Reset Sequences
Try these before calling a technician
LG
Press 'Jet Cool' + 'Sleep' simultaneously for 5 seconds
Works on most LG split ACs
Daikin
Turn off at MCB, wait 5 minutes, turn back on
Clears most temporary faults
Voltas
Press 'Mode' + 'Fan Speed' for 3 seconds on remote
Resets to factory defaults
Samsung
Hold 'Temp Down' + 'Fan Speed' for 5 seconds
Clears E1–E3 sensor errors
Panasonic
Turn off at MCB for 10 minutes, then restart
Required for H-series codes
All Brands
MCB Hard Reset: Off for 5 min → On
Universal first step for any error
Always try the MCB hard reset first — turn off the circuit breaker for 5 minutes, then restart. This clears 30–40% of temporary error codes without any technician visit.
Common LG AC Error Codes (CH Series)
LG uses the CH prefix for all fault codes. CH05 (communication error) is the most common.
| Code | Meaning | Priority | Action |
|---|---|---|---|
| CH01 | Indoor room temperature sensor fault | Technician | Replace indoor NTC sensor — ₹300–500. DIY if comfortable with electronics. |
| CH02 | Indoor coil temperature sensor fault | Technician | Replace coil temperature sensor — ₹300–500. |
| CH03 | Outdoor temperature sensor fault | Technician | Replace outdoor ambient sensor — ₹300–500. |
| CH05 | Indoor/Outdoor communication error | Urgent | Check 3-core communication cable. If intact, PCB replacement needed — ₹2,000–5,000. |
| CH10 | Outdoor unit EEPROM error | Urgent | Outdoor PCB replacement — ₹3,000–6,000. Call technician. |
| CH21 | Outdoor current sensor fault | Urgent | Outdoor PCB or current sensor replacement. |
| CH23 | DC peak current protection | DANGER | Stop AC. Check power supply stability. Call technician. |
| CH34 | Outdoor discharge temperature sensor fault | Technician | Replace discharge temperature sensor. |
| CH38 | Outdoor temperature sensor fault | Technician | Replace outdoor NTC sensor — ₹300–500. |
| CH67 | Outdoor fan motor fault | Urgent | Check outdoor fan capacitor first (₹300). If fan still fails, motor replacement — ₹1,500–3,000. |
Daikin AC Error Codes & Troubleshooting (U, L, E Series)
Daikin uses letter-prefix codes. U-series = refrigerant/pressure. E-series = outdoor unit. A-series = indoor unit.
| Code | Meaning | Priority | Action |
|---|---|---|---|
| A1 | Indoor PCB fault | Urgent | Indoor PCB replacement — ₹2,000–5,000. Call Daikin service. |
| A3 | Drain level sensor fault / drain pump error | Technician | Clear drain pipe blockage first. If persists, float switch replacement. |
| A5 | Freeze protection / high pressure protection | Urgent | Clean filter immediately. If persists, check refrigerant level. |
| A6 | Indoor fan motor fault | Urgent | Fan motor or capacitor replacement — ₹1,500–3,000. |
| C4 | Heat exchanger sensor fault | Technician | Replace thermistor sensor — ₹400–600. |
| C9 | Remote controller sensor fault | DIY | Replace remote controller — ₹800–1,500. |
| E1 | Outdoor PCB fault | Urgent | Outdoor PCB replacement — ₹3,000–6,000. |
| E3 | High pressure protection | Urgent | Clean outdoor unit coil. Check for airflow obstruction. Call technician. |
| E4 | Low pressure protection | DANGER | Stop AC. Refrigerant leak check required — call technician. |
| E7 | Outdoor fan motor fault | Urgent | Fan motor replacement — ₹1,500–3,000. |
| E9 | Expansion valve fault | Urgent | EEV replacement — ₹2,000–4,000. Call Daikin service. |
| H6 | Indoor fan motor fault | Urgent | Indoor blower motor replacement — ₹1,500–3,000. |
| L3 | Electrical box temperature high | Technician | Ensure 30cm clearance around outdoor unit. Clean condenser coil. |
| U0 | Refrigerant shortage | DANGER | Stop AC. Leak detection and gas refill — ₹1,500–3,000. |
| U4 | Indoor/Outdoor communication error | Urgent | Check inter-unit cable. PCB replacement if wiring is intact. |
Voltas & Blue Star Error Codes: The Indian Reliability Guide
Voltas and Blue Star share similar code structures. P4 (compressor discharge) is the most critical — stop AC immediately.
Voltas Error Codes
| Code | Meaning | Priority |
|---|---|---|
| E1 | Indoor ambient sensor open/short | Tech |
| E2 | Indoor coil sensor open/short | Tech |
| E3 | Outdoor coil sensor fault | Tech |
| E4 | Outdoor ambient sensor fault | Tech |
| E5 | Outdoor discharge sensor fault | Tech |
| E6 | Communication error | Urgent |
| P1 | High voltage protection | Urgent |
| P2 | Low voltage protection | Urgent |
| P4 | Compressor discharge temperature high | DANGER |
| F1 | Indoor fan motor fault | Urgent |
Blue Star Error Codes
| Code | Meaning | Priority |
|---|---|---|
| E1 | Room temperature sensor fault | Tech |
| E2 | Coil temperature sensor fault | Tech |
| E4 | Outdoor sensor fault | Tech |
| E6 | Communication error | Urgent |
| P1 | High voltage protection | Urgent |
| P4 | Compressor discharge temperature high | DANGER |
Troubleshooting Wizard
Deeper symptom diagnosis
Repair Cost Guide
Fair pricing before calling a tech
AC Spares Directory
Find sensors, remotes & capacitors
Maintenance Guide
Prevent 80% of error codes
Error Code FAQ
Expert answers to the most urgent questions