Voltas Air Conditioner

E4

How to Fix Voltas Air Conditioner Error E4

Voltas split AC error E4 indicates the indoor unit temperature sensor has failed or is reading erratic values. The AC will run but cooling efficiency drops.

Fixable at home 25 min Skill: intermediate

Updated April 2026 · Cross-referenced with Voltas service manual

Quick fix: Turn the AC off at the MCB for 10 minutes, then turn back on. A thermistor glitch clears with a full power-cycle about 40% of the time.

What error E4 means

Voltas split AC error E4 indicates the indoor unit temperature sensor has failed or is reading erratic values. The AC will run but cooling efficiency drops.

Safety first

Safety: Do NOT open the indoor unit cover while powered on. Turn off the MCB at your main panel before any inspection.

Step-by-step fix

  1. 1

    Step 1

    Full power-cycle

    Turn off the AC from the remote. Then turn off the dedicated AC MCB at your main electrical panel. Wait 10 minutes. Restore power.

  2. 2

    Step 2

    Check the indoor unit sensor

    Remove the indoor unit front cover (4 Philips screws, 2 at the bottom + 2 behind the filter cover). Locate the thermistor — a small cylindrical sensor on a wire near the evaporator coil.

  3. 3

    Step 3

    Inspect for loose connector

    The thermistor plugs into the PCB via a small 2-pin connector. Push it in firmly — vibration loosens this over time.

  4. 4

    Step 4

    Clean the evaporator coil

    While the cover is off, wipe the fins of the evaporator coil with a soft cloth. A thick layer of dust on the coil can distort sensor readings.

  5. 5

    Step 5

    Test for thermistor resistance

    With a multimeter in resistance mode, measure the thermistor: should read 10–15 kΩ at room temperature. Anything outside 5–25 kΩ means the sensor is faulty.

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When to call a technician

  • • E4 persists after power-cycle and connector check
  • • Multimeter shows thermistor outside 5–25 kΩ range
  • • AC is under Voltas warranty — attempting a self-repair voids coverage

Frequently asked questions

What does E4 mean on Voltas split AC?

Indoor temperature sensor (thermistor) fault. The AC loses feedback on ambient temperature, causing inefficient cooling and this error code.

Can I still use my AC with E4?

Yes, but the cooling will be uneven — the AC can't regulate the compressor based on room temp. Fix it within a week to avoid compressor wear.

How much does a Voltas thermistor cost?

₹250–450 for the sensor itself. Labour for installation at an authorised service centre: ₹400–800.

Affiliate disclosure: Tool links go to Amazon.in and may earn us a small commission at no extra cost to you. All guides are informational — follow safety warnings before attempting any fix. If in doubt, call a certified Voltas technician.