🔧 Inverter AC Error Codes? Complete Brand-Wise Troubleshooting Guide
Problem Overview
Your inverter AC's digital display is showing an error code like E1, F2, H4, or C5, and you're not sure what it means or how to fix it. Modern inverter air conditioners use alphanumeric error codes to communicate specific problems—from simple sensor issues to serious compressor failures. This comprehensive guide decodes error codes for top Indian AC brands (Daikin, LG, Samsung, Voltas, Blue Star) and provides clear troubleshooting steps for each code type.
Safety First
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Turn off power before inspecting: For any internal inspection or troubleshooting beyond basic reset, switch off AC at the circuit breaker to prevent electric shock.
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Never ignore critical error codes: Codes related to high pressure, overheating, or electrical faults can cause equipment damage or safety hazards if AC continues running. Turn off immediately.
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Warranty preservation: Opening sealed components or attempting refrigerant work will void warranty. For ACs under warranty, always contact authorized service centers.
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Document error codes: Take photo of error code display before resetting. If problem recurs, this information helps technicians diagnose faster.
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Refrigerant and compressor work: Error codes indicating refrigerant issues or compressor problems require professional technicians with specialized equipment—never attempt DIY repairs.
🔍 Quick Diagnosis Steps ⏱️ 2-5 minutes
1 Note the Exact Error Code
Write down or photograph the complete error code (letters and numbers). Error code format varies by brand: E1, F2, H04, C5, P1, etc. Exact code is crucial for diagnosis.
2 Identify Your AC Brand & Model
Check indoor unit nameplate for exact brand and model number. Different brands use same code letters for different problems (E1 means different things for Daikin vs LG).
3 Check Error Persistence
Turn AC off at remote and wall switch. Wait 5 minutes. Turn on again. If error clears and AC runs normally, it was likely temporary glitch. If error returns immediately, problem needs fixing.
4 Perform Basic Visual Checks
Before calling technician: Check if filters are extremely dirty, outdoor unit has obvious damage, drainage pipe is clogged, or circuit breaker has tripped. These cause many error codes.
5 Look for Pattern
Does error appear immediately on startup, after running 30 minutes, or only during high heat? Pattern helps diagnosis. Note what AC was doing when error appeared.
6 Check User Manual First
Your AC's user manual has brand-specific error code list. This guide covers common codes across brands, but manual has complete list for your exact model.
📋 Understanding Error Code Categories
E-Codes (E1-E9): Sensor & Communication Errors
E-series codes typically indicate sensor malfunctions, temperature reading errors, or communication problems between indoor and outdoor units. Common causes: faulty thermistor, loose wiring, PCB issues.
F-Codes (F1-F9): System Protection & Safety Faults
F-series codes indicate protective shutdowns: high/low pressure, overheating, overcurrent, or abnormal operation detected. AC stops to prevent damage. Often refrigerant or electrical issues.
H-Codes (H1-H9): Heating/Defrost Mode Issues
H-series codes relate to defrost cycle, heating operation (for heat pump ACs), or heat exchanger problems. May indicate frost detection, four-way valve issues, or outdoor temp sensor errors.
C-Codes (C4, C5, C9): Communication & Control Errors
C-series codes indicate communication failures between indoor/outdoor units, remote control issues, or inverter control board problems. Wiring, connection, or PCB-related errors.
🏭 Brand-Wise Error Code Tables
1️⃣ Daikin Error Codes
| Error Code | Problem Description | Likely Cause | DIY? |
|---|---|---|---|
| E0 | Outdoor unit PCB malfunction | Control board issue, voltage spike damage | ✗ |
| E1 | Indoor/outdoor unit communication error | Loose wiring, damaged cable, PCB fault | △ |
| E3 | High pressure protection activated | Overcharged refrigerant, dirty condenser, blocked airflow | △ |
| E4 | Low pressure protection | Refrigerant leak, undercharged system | ✗ |
| E5 | Compressor overload/overheating | Compressor running too hot, electrical issue | ✗ |
| E6 | Compressor locked/stuck | Compressor seized, capacitor failed | ✗ |
| E7 | Fan motor failure (outdoor) | Fan motor damaged, capacitor fault | ✗ |
| F3 | Discharge temperature too high | Low refrigerant, compressor issue | ✗ |
| H0 | Sensor malfunction (compressor) | Thermistor sensor failed or disconnected | ✗ |
| H9 | Outdoor air temperature sensor | Ambient temp sensor faulty | ✗ |
2️⃣ LG Error Codes
| Error Code | Problem Description | Likely Cause | DIY? |
|---|---|---|---|
| CH01 | Room temperature sensor error | Indoor thermistor disconnected or faulty | ✗ |
| CH02 | Heat exchanger sensor error | Evaporator coil sensor faulty | ✗ |
| CH05 | Outdoor unit temperature sensor | Condenser sensor malfunction | ✗ |
| CH06 | Fan motor RPM abnormal | Indoor blower fan issue, motor failing | ✗ |
| CH07 | Compressor position error | Inverter compressor control issue | ✗ |
| CH10 | Water full/drainage problem | Drain pipe clogged, pump malfunction | ✓ |
| CH11 | Communication error | Wiring between indoor/outdoor units | △ |
| CH38 | Outdoor unit overheat protection | Dirty condenser coils, high ambient temp | △ |
| CH52 | Compressor startup failure | Capacitor fault, compressor locked | ✗ |
| CH54 | Inverter compressor overcurrent | Electrical overload, compressor issue | ✗ |
3️⃣ Samsung Error Codes
| Error Code | Problem Description | Likely Cause | DIY? |
|---|---|---|---|
| E101 | Indoor room temp sensor error | Thermistor sensor faulty or disconnected | ✗ |
| E121 | Indoor heat exchanger sensor | Evaporator coil sensor malfunction | ✗ |
| E154 | Indoor fan motor error | Blower motor failure, wiring issue | ✗ |
| E221 | Outdoor heat exchanger sensor | Condenser temp sensor faulty | ✗ |
| E251 | Outdoor fan motor error | Condenser fan motor or PCB fault | ✗ |
| E401 | Compressor overheat protection | Compressor running too hot, low refrigerant | ✗ |
| E416 | High pressure protection | System overcharged, dirty coils, blockage | △ |
| E458 | Compressor overcurrent | Electrical overload, compressor fault | ✗ |
| E461 | Inverter communication error | PCB communication failure, wiring | △ |
| E554 | Outdoor unit overload | Compressor overload, voltage issue | ✗ |
4️⃣ Voltas Error Codes
| Error Code | Problem Description | Likely Cause | DIY? |
|---|---|---|---|
| E1 | Room temperature sensor fault | Indoor thermistor issue | ✗ |
| E2 | Indoor coil sensor error | Evaporator sensor faulty | ✗ |
| E3 | Fan speed error (indoor) | Blower motor or hall sensor issue | ✗ |
| E4 | Outdoor coil sensor fault | Condenser sensor malfunction | ✗ |
| E5 | Communication error (I/O) | Wiring or connection problem | △ |
| E6 | High pressure protection | Overcharged, dirty coils, blockage | △ |
| E7 | Compressor drive error | Inverter board or compressor fault | ✗ |
| F0 | Outdoor ambient sensor | Outdoor temp sensor faulty | ✗ |
| F1 | Discharge temperature sensor | Compressor discharge sensor issue | ✗ |
| F2 | Compressor overload protection | Overheating, electrical overload | ✗ |
5️⃣ Blue Star Error Codes
| Error Code | Problem Description | Likely Cause | DIY? |
|---|---|---|---|
| E0 | EEPROM error | PCB memory chip fault | ✗ |
| E1 | Indoor/outdoor communication | Connection or wiring issue | △ |
| E2 | Zero-crossing signal error | Power supply issue, PCB fault | ✗ |
| E3 | Indoor fan motor malfunction | Blower motor or control failure | ✗ |
| E4 | Indoor temp sensor error | Room thermistor faulty | ✗ |
| E5 | Indoor coil sensor error | Evaporator sensor malfunction | ✗ |
| E6 | Outdoor defrost sensor | Defrost sensor faulty (heat pump models) | ✗ |
| E7 | Outdoor coil sensor error | Condenser temp sensor issue | ✗ |
| E8 | Compressor top sensor error | Compressor temp sensor faulty | ✗ |
| P0 | IPM module protection | Inverter power module fault | ✗ |
🛠️ DIY Troubleshooting & Reset Procedures
Universal AC Reset Procedure
Works for most error codes across all brands:
• Turn off AC using remote control
• Switch OFF circuit breaker or disconnect power at main switch
• Wait 5-10 minutes (allows capacitors to fully discharge, system to reset)
• Switch power back ON at breaker
• Turn AC on using remote, set to cooling mode 18°C
• Observe if error code clears and AC operates normally
Check & Clean Air Filters (For E3, E6, H1 codes)
Dirty filters cause multiple error codes by restricting airflow:
• Turn off AC completely
• Open indoor unit front panel (usually lifts up or slides)
• Remove mesh filters—check if heavily clogged with dust
• Wash filters with mild detergent and water, gentle scrubbing
• Rinse thoroughly, shake off water, air dry completely (2-3 hours)
• Reinstall dry filters, close panel
• Reset AC using power cycle method above
Inspect Outdoor Unit for Blockages (For E3, E6, F3 codes)
High pressure/temperature errors often caused by obstructed outdoor unit:
• Ensure outdoor unit fan is spinning when AC runs
• Check for debris, leaves, plastic bags blocking condenser fins
• Clear at least 2 feet of space on all sides of outdoor unit
• Look for bird nests, spider webs in fan area
• Gently remove visible obstructions (power off first)
• Ensure unit is not enclosed in tight space without ventilation
Verify Wiring Connections (For E1, E5, C4, C5, CH11 codes)
Communication errors often indicate loose wiring:
• Turn OFF power at circuit breaker
• Check control cable between indoor and outdoor units
• Look for damaged insulation, rodent damage, water exposure
• Ensure cable connections at both units are tight (don't over-tighten)
• Check for pinched cables, sharp bends, or crushing damage
• Inspect terminal block connections—should be secure, no corrosion
Check Drainage System (For CH10, water-related errors)
Water full or drainage errors indicate blocked drain:
• Turn off AC
• Locate drain pipe from indoor unit (usually PVC pipe going outside)
• Check if water drips from drain during AC operation
• If no dripping, drain is clogged—debris, algae, or insect blockage
• Use thin wire or compressed air to clear drain line
• Pour cup of warm water with vinegar through drain pan to clean
• Ensure drain pipe has proper downward slope, no kinks
Voltage Check (For E7, compressor-related errors)
Low voltage can trigger compressor protection errors:
• Check if other high-power appliances are running on same circuit
• Use multimeter to measure voltage at AC outlet (should be 220-240V)
• If voltage consistently below 200V, electrical supply issue
• Install voltage stabilizer (₹2,000-₹5,000) for compressor protection
• Dedicated 15A circuit recommended for inverter ACs
• Contact electrician if voltage fluctuates widely
Brand-Specific Reset Methods
Daikin: Press and hold both temperature up/down buttons on remote for 5 seconds
LG: Remove batteries from remote, unplug AC for 10 minutes, restore power, replace batteries
Samsung: Press "Options" + "Sleep" buttons simultaneously on remote for 3 seconds
Voltas: Press "Turbo" + "Timer" buttons together for factory reset
Blue Star: Power off at breaker, wait 15 minutes, power on—no button reset needed
📞 When to Call a Professional
🔴 Critical Errors - Immediate Professional Help
- • Compressor errors (E5, E6, E7, CH52, E458, F2)
- • High/low pressure protection (E3, E4, E416, E6)
- • Inverter module failures (P0, P1, E461)
- • Refrigerant-related codes (F3, E4, low cooling)
- • Repeated error after reset (underlying fault)
- • Burning smell or sparks with any error code
🟡 Sensor & Component Replacement
- • Temperature sensor errors (E1, E2, CH01, E101, E4)
- • Fan motor failures (E7, CH06, E154, E251, E3)
- • PCB/communication errors (E0, E1, E5, C4, CH11)
- • Persistent drainage issues after cleaning (CH10)
- • Error code not listed in manual or this guide
💰 Expected Repair Costs by Error Type (2025 India)
Wiring/Connection Fix: ₹300-₹1,500
Drain Cleaning (Pro): ₹500-₹1,000
Capacitor Replacement: ₹300-₹800
PCB Repair: ₹2,500-₹7,000
Refrigerant Work: ₹2,000-₹5,000
General Service Visit: ₹500-₹1,500
📋 Information to Provide Technician
- • Exact error code (photo of display screen)
- • AC brand, model number, and age/installation date
- • When error first appeared and frequency of occurrence
- • What AC was doing when error occurred (cooling, just started, running 2 hours, etc.)
- • Any unusual sounds, smells, or visual issues
- • Recent maintenance history, last service date
- • Warranty status (critical for free repairs)
🛡️ Preventive Care & Error Code Prevention
Every 2 Weeks
Clean air filters, check drainage flow, inspect outdoor unit for debris, verify error-free operation during test run
Twice Yearly
Professional deep cleaning, sensor calibration check, wiring inspection, refrigerant pressure verification, capacitor testing
Electrical Protection
Install voltage stabilizer, dedicated circuit, surge protector—prevents 60% of error codes caused by power issues
💡 Error Code Prevention Checklist:
- • Voltage stabilizer: Protects against E5, E6, E7, compressor errors from power fluctuations
- • Regular filter cleaning: Prevents E3, E6, H1 high-pressure and airflow errors
- • Annual professional service: Catches sensor drift, wiring issues before they cause shutdowns
- • Proper installation: Correct refrigerant charge, wiring, drainage prevents 70% of error codes
- • Avoid extreme settings: Don't set AC to 16°C in 45°C heat—stresses system, triggers protection
- • Outdoor unit maintenance: Keep condenser clean, shaded, well-ventilated to prevent overheating errors
- • Immediate attention to errors: Don't ignore recurring codes—small issues become expensive repairs
❓ Frequently Asked Questions
Q1: Error code keeps coming back after reset. What does this mean?
Recurring error indicates genuine hardware or system problem, not temporary glitch. Reset only clears the code display—underlying fault remains. Common recurring errors: E1 (communication wiring damaged), E4 (refrigerant leak), E5 (failing compressor capacitor), E7 (motor bearing wear). Document error pattern (how long before it returns) and call technician—problem will worsen if ignored.
Q2: Can I ignore error code if AC still seems to work?
Absolutely NOT. Error codes are protective mechanisms preventing equipment damage or safety hazards. Even if AC appears functional, it's operating abnormally. Example: E3 high-pressure code means system is overworked—can damage compressor permanently. E4 low-pressure indicates refrigerant leak—compressor will fail without proper gas. Address all error codes promptly to avoid costly repairs later.
Q3: Same error code on different brands—are they the same problem?
NO—error codes are NOT universal across brands. E1 means "communication error" for Daikin but "room sensor fault" for Voltas. E3 is "high pressure" for some brands, "fan motor error" for others. Always refer to your specific brand's manual or this guide's brand-specific tables. Using wrong brand's code interpretation leads to misdiagnosis and incorrect repairs.
Q4: How do I find error code if display only shows blinking lights, no text?
Older or basic AC models use LED blink patterns instead of text codes. Count number of blinks, note pattern (e.g., 3 blinks, pause, 2 blinks = Code 32). Refer to your manual's LED code table—usually in troubleshooting section. Some brands: continuous blinks = sensor error, alternating indoor/outdoor LEDs = communication error. Take video of blink pattern to show technician if unclear.
Q5: Error appeared after power outage. Is AC damaged?
Likely not damaged—power surges during outages can trigger temporary error codes. Perform full reset: turn off breaker 10 minutes, restore power, test AC. If error clears and doesn't return, AC is fine. Install surge protector to prevent future issues. However, if error persists after reset or AC behaves abnormally, power surge may have damaged PCB or compressor—needs professional check.
Q6: How long does typical error code repair take?
Depends on fault type: Sensor replacement: 30-60 minutes | Wiring repair: 1-2 hours | Filter/drain cleaning: 30 minutes | Capacitor replacement: 45 minutes | Refrigerant work (leak repair + refill): 2-4 hours | Compressor replacement: 4-8 hours | PCB replacement: 1-2 hours. Add time for diagnosis (30-60 min) and parts procurement if technician doesn't carry part. Schedule accordingly.
Q7: Is it worth repairing old AC showing error codes, or better to replace?
Cost-benefit analysis: If AC is 8+ years old AND repair cost exceeds 40% of new AC price, consider replacement. Example: 10-year-old AC needs ₹12,000 compressor repair—new 5-star inverter AC costs ₹30,000. Better to replace and save on electricity. However, for ACs under 5 years, most repairs are cost-effective. Factor in: repair cost, age, warranty status, energy efficiency improvement of new models.
Q8: Do all inverter ACs have self-diagnostic error codes?
Yes, all modern inverter ACs (2015 onwards) have built-in diagnostics with error codes. Non-inverter/fixed-speed ACs may have basic error indication but fewer specific codes. Inverter technology requires precise monitoring of compressor speed, current, temperature—hence extensive error code system. If your AC doesn't show error codes during malfunction, it's likely older non-inverter model—technician uses manual diagnosis.
⚠️ Disclaimer: This error code guide is for informational and diagnostic purposes only. Error codes indicate specific faults but don't replace professional diagnosis with proper tools (multimeters, pressure gauges, leak detectors). Refrigerant work, compressor repairs, and electrical troubleshooting require certified technicians. Never attempt to open sealed components or handle refrigerant yourself. Always verify warranty status before repairs—unauthorized service voids coverage. When in doubt, contact brand-authorized service centers. Information based on common error codes as of 2025—specific models may vary.
Important Safety Reminder
If you're not comfortable with any step, or if the problem persists after trying these solutions, please contact a qualified technician. Safety should always be your first priority when dealing with electrical appliances.
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