What to check yourself
Step 1. Run the hot tap at the sink first, then start the machine
Free, takes a minute, and it explains a real share of these. A dishwasher plumbed into the hot line pulls whatever is sitting in the pipe. If the machine is a long way from the water heater, the first fill can be cold, the machine never catches up and reports a heating fault it did not cause. Run the nearest hot tap until it is genuinely hot, then start the cycle.
Step 2. Check the water heater setting
Most machines expect an incoming supply around 120°F. A heater turned down to save energy, or one that has quietly failed, produces exactly this. If the hot tap in the kitchen never gets properly hot, the problem is not the dishwasher.
Step 3. Cut the power for ten minutes
A reset clears the fault if a single bad temperature reading latched it. If the code returns on the next cycle, the fault is real and the reset has told you something useful for nothing.
Step 4. Notice whether the water is warm at all
Open the door part way through a wash and feel the steam or the water on the door. Warm but not hot points at the sensor or the supply; stone cold points at the heating element or its circuit. Telling a technician which one you saw saves them a visit's worth of guessing.
If the water is hot you will get a face full of steam. Open the door slowly and stand back.
What a technician will look at
Described so you know what you are paying for, not as steps to repeat.
Test the element, the thermistor and the board
Three parts can produce this and only a meter tells them apart: the heating element itself, the temperature sensor reading it, and the board that should be switching power to the element. Testing costs a fraction of replacing the wrong one.
When to call a technician
Once a hot start and a reset have not helped. There is no owner level check that separates a dead element from a bad sensor, and guessing means buying one part to find out you needed the other.
What the repair costs
| Repair | Part only | Fitted by a technician |
|---|---|---|
| Running the hot tap first, if the supply was the issue | - | Free |
| Diagnosis alone | - | $75 to $130 |
| Heating element replacement | $25 to $75 | $200 to $350 |
| Control board replacement | - | $300 to $550 |
A new machine of the same class runs $500 to $1,500. Once a quote passes about a third of that on an older appliance, the repair stops making sense.
Codes people confuse this with
Questions people ask
- Is it safe to keep using it with cold water?
- Safe, yes. Effective, no. Grease does not shift below about 120°F, so plates come out greasy and glasses cloudy, and no cycle is sanitising anything. It is a fair stopgap for a week, not a way to live.
- The dishes are wet at the end. Related?
- Almost certainly the same fault. Most drying on these machines is residual heat from the final hot rinse. No heat, no drying, whether or not the machine tells you why.
- Should I just replace the heating element myself?
- Only if you have tested it. The element, the sensor and the board all produce this code, and the element is the one people buy first because it is the one they have heard of. A meter costs less than the wrong part.
Which machines this applies to
Applies to
LG dishwashers across the LDF, LDT, LDP and LSDF ranges. LG uses HE both for water that will not heat and for water that has overheated; overheating above the safety limit usually shows as tE instead.
Last checked
2026-08-10