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Error code reference
LG Heat Pump Error Code 21
DC peak: IPM over current, temperature, or compressor malfunction occurred 3 times in 1 hour.
SourceLG Heat Pump Air Conditioner - Service Manual: CRUN/CRNN Seriesp. 231-232
Diagnostic procedure
The full 21 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
1
First diagnostic step
Check IPM terminal connections; remove all cables from compressor and check if CH21 recurs; check for water leakage into IPM signal terminal.
SourceLG Heat Pump Air Conditioner - Service Manual: CRUN/CRNN Seriesp. 231-232
More steps, wiring diagram references, and verified part numbers
Includes expected resistance and voltage values, connector pinouts, and supersession notes for replacement parts.
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Where this code is documented
2 manuals in the MyPros+ library document this code for LG heat pump.
Models covered by the manuals that document this code
75,000+ service documents · 20,000+ error codes · 100+ brands
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