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Error code reference
LG Air Conditioner Error Code CH21
DC Peak (IPM Fault) - PCB IPM section current exceeds 32-38A range, compressor turns OFF.
SourceLG Air Conditioner - Tech Sheet: LP-Y Series Specifications
Diagnostic procedure
The full CH21 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 fan constraint (indoor/outdoor); remove blockings around heat exchanger and filter; check SVC valve lock; check overcharge/refrigerant leakage; check pipe folding.
SourceLG Wall Mounted Air Conditioner - Service Manual: General Inverter Typep. 28, 56-57
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 air conditioner.
Models covered by the manuals that document this code
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