Error code reference

Samsung Heat Pump Error Code P4

Reverse phase or open phase error - 3 phase power L1(R)-L2(S)-L3(T) order is reversed or power is missing on one or more phases.

SourceSamsung Heat Pump - Service Manual: Troubleshooting Guide (AVMBH020CA0XAG)p. 179, 187

Samsung codes Samsung heat pump codes

Diagnostic procedure

The full P4 procedure

Step 1 is visible so you can confirm you are on the right page. The remaining steps, the ones that tell you whether to actually replace a part, unlock with any pass.

MyPros+ · DiagnosticsStep 1 preview

First diagnostic step

Check CN77 cable voltages red~white/white~black/red~black for AC380V; if normal, exchange two wires of 3 phase incoming power and press reset key (K3).

SourceSamsung Heat Pump - Service Manual: Troubleshooting Guide (AVMBH020CA0XAG)p. 179, 187

Unlock with pass

More steps, wiring diagram references, and verified part numbers

Includes expected resistance and voltage values, connector pinouts, and supersession notes for replacement parts.

Unlock P4 procedure $9.95

Or subscribe: $29/month for all codes plus Max diagnostics, with 70 Max messages a day. Plus applicable tax.

Where this code is documented

11 manuals in the MyPros+ library document this code for Samsung heat pump.

Models covered by the manuals that document this code

75,000+ service documents · 20,000+ error codes · 100+ brands

Get Started

$29/month · Cancel anytime · Or $9.95 3-day pass · Plus applicable tax

The full P4 procedure

Where this code is documented

Models covered by the manuals that document this code

Related Samsung heat pump error codes