LG refrigerator sensor errors indicate thermistor (temperature sensor) failures. Er FS (freezer sensor) can be tested—normal reading is 2.07K-2.54K ohms at room temperature. Er rS (refrigerator sensor) officially has “no troubleshooting steps” per LG—professional service required. Er IS/Er 15 often indicates door hinge wiring damage.
| Error Code | Er FS / Er rS / Er IS |
|---|---|
| Meaning | Temperature sensor failure (freezer, refrigerator, or ice maker) |
| Difficulty | Moderate |
| Time to Fix | 30 minutes to professional service |
| Tools Needed | Digital multimeter, Screwdriver set |
| DIY Fixable | Yes |
| Official Source | LG Support |
Sensor errors indicate the control board isn’t receiving valid temperature readings from one or more thermistors. Some sensors are DIY-testable; others require professional service.
Understanding Sensor Errors
| Code | Sensor | DIY Testable? | Notes |
|---|---|---|---|
| Er FS | Freezer temperature | Yes | Test resistance at pins 17-18 |
| Er rS | Refrigerator temperature | Limited | LG says “no troubleshooting steps” |
| Er IS | Ice maker sensor | Limited | Check door hinge wiring |
| Er SS | Pantry/special compartment | No | Professional service |
| Er rt | Room temperature | No | Professional service |
| Er HS | Humidity sensor | No | Professional service |
Er FS — Freezer Sensor Failure
The freezer sensor monitors interior freezer temperatures and sends readings to the main control board.
Symptoms
- Warmer-than-usual freezer temperatures
- Longer compressor run times
- Continuous frost buildup
- Food spoilage
DIY Testing Procedure
- Unplug refrigerator
- Access main control board (location varies by model)
- Find wire connector CON7
- Locate freezer sensor wires at pins 17 and 18
- Disconnect and measure resistance
Expected readings:
| Condition | Resistance |
|---|---|
| Room temperature (77°F) | 2.07K-2.54K ohms |
| Zero ohms | Direct short—replace sensor |
| OL (infinite) | Open circuit—replace sensor |
Replacement
If sensor tests bad, replace the freezer thermistor. Part costs $30-80 depending on model. The sensor typically mounts inside the freezer compartment behind a panel.
Er rS — Refrigerator Sensor Failure
The refrigerator compartment R1 temperature sensor monitors the main fresh food section.
Important Notice
LG officially states: “Unfortunately, there are no troubleshooting steps for this error code. The unit will require a repair service.”
What You Can Try
- Power reset — Unplug for 5 minutes, restore power
- Check for obstructions — Food items blocking sensor area
- Clear ice/frost — If visible around sensor location
Testing (Advanced)
If you want to test despite LG’s guidance:
Refrigerator sensor resistance range:
- Varies significantly with temperature: 6.2K-225K ohms depending on temperature from -39°F to 104°F
- At room temperature (~77°F): approximately 10K-15K ohms
If testing shows normal resistance but error persists, the control board may be at fault.
Er IS / Er 15 — Ice Maker Sensor
This error indicates a problem with the in-door ice maker’s fan motor or sensor disconnection.
Display Confusion
Note: “Er IS” and “Er 15” can display identically on some models:
- “I” looks like “1”
- “S” looks like “5”
Both indicate the same ice maker sensor issue.
Common Cause: Door Hinge Wiring
The most common cause is wire damage at the door hinge. The wiring that runs through the door hinge flexes every time you open the door—over time, this repeated flexing can break wires inside the insulation.
DIY Inspection
- Examine the wiring harness at the top door hinge
- Look for visible damage, pinching, or wear
- Check the connector for corrosion or loose pins
- If wires appear damaged, they need repair or replacement
Other Causes
- Ice maker sensor failure
- Moisture/corrosion on electrical connections
- Complete ice maker assembly failure
If Er IS appears intermittently—sometimes showing, sometimes clearing—the problem is almost certainly a loose connection or damaged wire at the door hinge. The intermittent contact happens as the door moves.
Other Sensor Errors
Er SS — Pantry Sensor
Monitors the deli/pantry drawer temperature. No DIY troubleshooting available—professional service required.
Er rt — Room Temperature Sensor
Monitors ambient temperature around the refrigerator. Located near the condenser area. Professional service required.
Er HS — Humidity Sensor
Monitors moisture levels in the refrigerator. Professional service required.
Er It — Ice Maker Motor/Defect
Different from Er IS—this indicates an internal defect in the ice maker assembly itself (motor, Hall IC sensor, or mold thermostat).
DIY attempt: Reset ice maker (hold TEST/FILL 3-5 seconds), manual defrost if mechanism is frozen.
General Troubleshooting Steps
Step 1: Power Reset
Always try this first for any sensor error:
- Unplug refrigerator
- Wait 5 minutes
- Restore power
- Monitor for 24 hours
Step 2: Check Connections
If error returns:
- Access the affected sensor’s wiring
- Check for loose connections
- Look for visible damage
- Reseat connectors firmly
Step 3: Test Sensor
For DIY-testable sensors (FS, IS):
- Disconnect sensor wires
- Measure resistance with multimeter
- Compare to specifications
- Replace if out of range
Step 4: Professional Service
If reset and testing don’t resolve the issue, or for sensors without DIY steps (rS, SS, rt, HS), contact LG support.
Model Coverage
Sensor errors appear on all LG refrigerator types:
- French Door: LRMVS, LRMVC, LRFXS series
- Side-by-Side: LRSXS, LRSVS series
- InstaView: All models
- Bottom/Top Freezer: Various models
Sensor locations vary by model—consult your service manual for exact positions.
When to Call a Tech
Contact LG support (1-800-243-0000) if:
- Er rS appears (professional service recommended by LG)
- Er SS, Er rt, or Er HS appear (no DIY steps)
- Sensor tests good but error persists
- You’re not comfortable with electrical testing
- Error returns immediately after replacement
Sources
For official LG support: