Heat Pump Service Manuals & Error Codes

Service manuals, error codes, and parts diagrams for heat pump repair across all major brands.

240Manuals

686Error Codes

5Brands

MyPros+ Max

Get step-by-step heat pump diagnostics from the service manual.

Step-by-step tests with expected resistance, voltage, and continuity values
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M+

M+ Max·Whirlpool Heat Pump

My appliance shows an error code

M+

Control board fault diagnosis

From Tech Sheet W10810403, p.8:

1.Access the service diagnostic mode using the tech sheet procedure. Record all stored fault codes from the error history, not just the most recent active code.

2.Measure control board supply voltage at the test points. Expected: 12 VDC and 5 VDC. A drop below 4.75 VDC on the logic rail points to a failed onboard regulator.

3.Inspect all connectors on the main control board for corrosion, thermal stress, or backed-out pins. Reseat each connector with the power disconnected.

Part WPW10804018

Electronic control board

Top Error Codes for Heat Pump Repair

CodeBrandDescription

01LGIndoor unit air sensor (room temperature sensor) open or short...02LGIndoor unit inlet pipe sensor open or short circuit detected.03LGWired remote controller to indoor unit transmission error — no signal...04LGDrain pump malfunction — float switch sends full signal despite drain...05LGOutdoor unit to indoor unit transmission error — no signal received...06LGIndoor unit outlet pipe sensor open or short circuit detected.07LGIndoor unit is operating in a different mode than other connected...09LGSerial number error — EEPROM serial number on indoor unit is 0 or...21LGDC peak — IPM over current, temperature, or compressor malfunction...22LGMax CT — current detection exceeds the maximum current limit.23LGDC link — DC charging not performed within 45 seconds after starting...24LGHigh pressure — compressor off occurred 3 times in 1 hour due to high...25LGLow/over voltage — input voltage is out of tolerance of rating...32LGInverter compressor discharge temperature — compressor off occurred 3...33LGConstant speed compressor discharge temperature — compressor off...

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Access 240 service manuals, 686 error codes, and step-by-step diagnostics for heat pump repair.