What Does This Error Mean?

Keurig coffee that comes out lukewarm is most often caused by scale buildup coating the heating element. Descale the Keurig and then raise the temperature to the maximum setting in Settings > Temperature if your model supports it.

Affected Models

Keurig K-Elite
Keurig K-Supreme
Keurig K-Supreme Plus
Keurig K-Café
Keurig K-Select
Keurig K-Classic

Common Causes

Scale buildup on the internal heating element reducing heat transfer efficiency
Temperature setting not at maximum — many Keurig models default to a lower brew temp
Pre-heat cycle incomplete — brewing too soon after turning on the machine
Using the 12 oz cup size, which passes more cooler water through the K-Cup
Cold water in the reservoir reducing the effective output temperature

How to Fix It

Raise the temperature setting to maximum.

On models with a digital display, go to Settings > Temperature and set it to the highest available level (usually 192°F / 89°C). The K-Elite, K-Supreme, and K-Café support this setting. Many Keurigs default to a mid-range temperature to reduce burn risk.
Allow the Keurig to fully pre-heat.

After turning the Keurig on, wait until the brew button is lit and steady — not blinking. Brewing the moment the button first lights up uses partially heated water. Allow 2–3 minutes for the machine to reach full operating temperature.
Descale the Keurig.

Scale coating the heating element is the leading cause of lukewarm Keurig coffee. Go to Settings > Maintenance > Descale and follow the descale procedure using Keurig descaling solution or a citric acid solution. Descaling typically restores full temperature output within one session.
Use a smaller cup size.

The 12 oz setting pushes the most water through the K-Cup, which dilutes the brew and lowers temperature. Switch to the 8 oz setting for a hotter, stronger result. Smaller cup sizes allow the heating element to maintain temperature throughout the entire brew cycle.
Use room-temperature water in the reservoir.

Filling the reservoir with cold refrigerator water or water straight from a cold tap forces the heater to do more work. Fill the reservoir with room-temperature water to reduce the thermal load on the heating element. This makes a noticeable difference when the Keurig is already running near its temperature limit.

When to Call a Professional

If the Keurig has been descaled and set to maximum temperature but coffee is still lukewarm after multiple brews, the heating element or thermostat may be failing. Contact Keurig support.