mypros+
Error code reference

LG Microwave Error Code E-33

Weight sensor error

LG codesLG microwave codes

Weight sensor error: initial value of K calculated by weight sensor is above or under +/-28 as value of HEX.

First step from the service manual

Check sensor.

The complete diagnostic procedure includes additional test steps, resistance specifications, wiring diagram references, and component test points.

MyPros+ Max

Get the full diagnostic procedure for E-33.

  • Step-by-step tests with expected resistance, voltage, and continuity values
  • Wiring diagram references and connector pinouts from the OEM service manual
  • Verified part numbers when replacement is required
Get the full procedure

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

What E-33 means on a LG microwave

The E-33 error code on an LG microwave indicates a weight sensor fault. Specifically, the microwave's internal calibration routine has calculated an initial K value from the weight sensor that falls outside the acceptable range of plus or minus 28 in hexadecimal. The K value is a calibration constant derived during the sensor's initialization sequence, and when this constant strays beyond the defined tolerance window, the control board flags E-33 and halts weight-based cooking functions.

The weight sensor in LG microwaves is used to enable automatic cooking modes that adjust time and power based on the mass of food placed on the turntable. The sensor generates an analog signal that the control board converts into a digital reading and uses to compute the K calibration value. If the sensor is delivering an out-of-range signal due to physical damage, contamination, wiring issues, or component drift, the computed K value will exceed the plus or minus 28 hex threshold and trigger this error.

Diagnosis should begin with a physical inspection of the weight sensor and its wiring harness. Check for loose connectors, damaged leads, or corrosion at the sensor terminals. If the wiring checks out, the sensor itself may have drifted out of specification or failed outright and will require replacement. In some cases the control board may be misreading the sensor signal due to a board-level fault, though a failed sensor is the more common finding.

Source: manufacturer service documentation.

Common causes of E-33

  1. 01

    Failed or out-of-spec weight sensor

    Part replacement

    The weight sensor itself may have drifted beyond its acceptable calibration range or suffered internal failure, causing the K value to exceed the plus or minus 28 hex tolerance. This is the most common root cause and typically requires sensor replacement.

  2. 02

    Loose or damaged sensor wiring harness

    Wiring / connection

    A disconnected, pinched, or corroded connector between the weight sensor and the control board can produce an erratic signal, causing the calibration constant to fall outside the acceptable range. Inspect all connectors and leads at the sensor and board.

  3. 03

    Contamination or debris on the sensor

    Wiring / connection

    Food residue, grease, or moisture on the weight sensor can interfere with its output signal and cause an abnormal initial reading. Clean the sensor and the area around it, then attempt to reset the unit.

  4. 04

    Physical damage to the sensor

    Part replacement

    Impact from a dropped turntable or heavy cookware can physically damage the weight sensor, altering its baseline output and making accurate calibration impossible. Look for visible cracks or deformation on the sensor body.

  5. 05

    Control board fault

    Part replacement

    If the sensor and wiring both test correctly, the main control board may be misinterpreting the sensor signal due to a component-level failure. This is the least common cause and is typically diagnosed after ruling out the sensor and wiring.

See the test procedure for each cause

Frequently asked questions about E-33

What does E-33 mean on a LG microwave?
E-33 indicates a weight sensor calibration error. During the sensor's initialization routine, the control board calculates a value called the K constant, and E-33 is triggered when that constant falls outside the allowed range of plus or minus 28 in hexadecimal. This prevents the microwave from using its automatic weight-based cooking functions until the sensor issue is corrected.
Can I fix the E-33 error myself on my LG microwave?
Some cases of E-33 can be addressed by a knowledgeable DIYer. Start by unplugging the microwave, inspecting the weight sensor for contamination or loose wiring, cleaning the sensor area, and reconnecting any loose harness connectors. If the error returns after these steps, the sensor likely needs to be replaced, which requires disassembling the microwave interior and working near high-voltage components. If you are not comfortable working inside a microwave, a qualified technician should handle the repair.
Is it safe to use my LG microwave while E-33 is displayed?
The E-33 error disables the automatic weight-based cooking modes, but basic microwave functions may still operate. However, using the appliance with an active fault code is not recommended, as the underlying sensor issue could indicate other problems with internal wiring or components. It is best to resolve the error before continued use.
Will resetting my LG microwave clear the E-33 error?
A reset by unplugging the microwave for a few minutes may temporarily clear the error code, but if the weight sensor or its wiring is faulty, the E-33 code will return the next time the sensor initialization routine runs. A reset alone is not a fix and should only be used as a first diagnostic step to confirm whether the fault is persistent.
How much does it cost to repair an E-33 error on a LG microwave?
Repair costs depend on whether the issue is a wiring problem or a failed sensor. If only a connector needs to be reseated, there may be no parts cost. If the weight sensor itself needs replacement, parts typically range from around 30 to 80 dollars depending on the model, with professional labor adding another 75 to 150 dollars or more. If the control board is at fault, repair costs can be significantly higher.

Related LG microwave codes

All LG microwave codes
View all 84 LG microwave codes

78,000+ service manuals · 160,000+ error codes · 55+ brands

Get Started

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