My Karcher T 21/1 keep turning itself off when I am using it. Not sure why.

My account pin on 0711825797

Try there tech support

Check to be sure that the GFI on the plug is not tripped. If that is ok, try turning the motor a little - use a screwdriver, stick it through the fan housing and move the fan 90 degrees. Then try turning it on. If it starts, the problem is with the motor starting to go bad.

I'm not a karcher dealer, but I'll comment. I'm assuming you've misplaced your owner's manual -- so the only way you'll know for sure is to contact karcher.com..... or a dealer.

That said, I'm pretty sure your blinking light is just bells and whistles kind of stuff. It most likely is a reminder that its time to change the diesel filter. Which means it has some "re-set" procedure. I just wouldn't worry about it.
Don

Check that you have sufficient inlet flow and pressure and that the inlet is not blocked in any way, both the supply hose and in the machine itself.

Also, be sure the cap is turned to the direction that lets the soap in. It has a gradation on it and if it is turned all the way to the smallest (cap fully closed) very little soap will be injected into the stream.

The most likely issue, which seems to occur alot with karcher, is a cracked water pump. What happens is that as you release the trigger on the handle, the rise in pressure should cut off the motor, but as it also cuts off the water flow at the wand end and the motor spins a few more revs until it stops, then there is a huge pressure glitch which blows apart the weak plastic pumps that they use. Since the plastic cracks it is very difficult to repair and the only option is to go and buy another. BUT...this time tape up the trigger on the handle so it is always on and then it won't blow itself up. Just use the unit on/off switch to turn the motor on and off.

Before you start it up:
1. Disconnect the high pressure hose 2. Connect the water supply and turn on 3. Make sure water is flowing through the pump
Start the motor, run for about 10 seconds and then turn off.
Turn off the water supply, connect the high pressure hose, turn water back on, start the motor and away you go.

these small power washers are tricky. Keep working with it. It may just be waiting for u to squeeze the trigger to activate. Make sure you have the water connected and turned on.