Blue Star Air Conditioner

Blue Star AC P4 error

Power supply voltage problem

You can usually fix itReported by one source — verify

Most people can clear this with the simple steps below.

We found this meaning in only one secondary source. Confirm it with your user manual or brand customer care before any repair.

What it means

The supply voltage is too low, too high or unstable, so the appliance stopped itself to avoid damage.

Common causes

Low or high mains voltage in your area
Stabilizer faulty, overloaded or of the wrong rating
Loose plug, socket or wiring
Short power cut or fluctuation

Try this at home first

Tick each step as you go

Wait until the voltage is normal, then restart
Use a correctly rated stabilizer if your model needs one
Check the plug and socket are tight and not burnt

When to call a technician

If the socket voltage is normal and the code repeats, have the wiring and board checked by an electrician or technician.

Safety first

Always switch off at the wall socket or MCB before touching any part. Do not open the outdoor unit, control boards or gas pipes yourself — they carry high voltage and pressure.

Frequently asked questions

What does P4 mean on a Blue Star Air Conditioner?

Power supply voltage problem. The supply voltage is too low, too high or unstable, so the appliance stopped itself to avoid damage.

Can I fix Blue Star Air Conditioner error P4 myself?

Usually yes. Start with: Wait until the voltage is normal, then restart.

Is it safe to keep using the Air Conditioner with P4?

Yes, once the cause is fixed.

Other Blue Star AC codes

L3 Outdoor fan motor fault L4 Current sensor (CT) fault LC Compressor start / rotation fault P1 Power supply voltage problem P2 Outdoor unit overheat protection P3 Overcurrent / compressor overload P5 Overcurrent / compressor overload P7 Inverter board / power module protection P8 Inverter board / power module protection PH Power supply voltage problem U4 Communication error (indoor ↔ outdoor unit)

All Blue Star Air Conditioner error codes

Same code on other brands

P4 Inverter board / power module protection / Power supply voltage problemVoltas AC P4 Inverter heat-sink temperature sensor faultDaikin AC

Sources

We write every explanation in our own words from these references.

Last checked: 2026-10-20