Jura impressa Z5 doesn't switch on anymore. A few days before just was displaying "maintenance" and then no more signs of life.

Error 4 is in Plain text a Temperature measurement error in steam cycle (circuit)

Causes / Remedy:

Sorted in order of likeliness !!!

1) Thermal sensor is defective. Determine the resistance value at 20 degrees C to be about 12kOhm. - Replace thermal sensor if not.
OR
2) Cable broken to the thermal sensor or oxidized contacts. - Replace / repair the cable.
OR
3) Logic board defective - replace electronics / replace EEPROM.

If you want to do the job yourself. Parts for repair solutions above are
1) Replacement Thermal Sensor with cable GBP 19.99 plus postage
2) if you can fix broken wire or oxidized contact no need for parts
3) logic board GBP 198.99 plus postage (there might be the possibility to have EEPROM on the board replaced at a fraction of the price. Defective board must be sent in first.

It also is possible to sent in the machine for repair.

Is it a J5 or Z5? Either way, you need to use fresh coffee beans with the coffee machine.

Trouble shooting guide is here:
Jura Coffee Machine

Hi, how to fix your Jura step by step, good luck... http://fixandparts.wix.com/nicknicoloudis#!jura-coffee-machine/c15gy

Hi, I made a video how to fix your Jura step by step, good luck.!
http://fixandparts.wix.com/nicknicoloudis#!jura-coffee-machine/c15gy

Hi, I made some videos how to fix your Jura step by step, good luck... http://fixandparts.wix.com/nicknicoloudis#!jura-coffee-machine/c15gy

how??

sent it back to jura

The common cause is that the frothing connection is faulty. You can look at the Guide to clean the Jura frothing connection, or try this. Take some bicarb or vinegar, dissolve in 400ml luke warm water, select cappuccino maintenance under the options, or press the milk button. Run the complete mixture through then. Run about 600ml of plain water through the spout. Turn the sport from froth to milk and back every 10 seconds.
If this does not work, then there may be a need to decal the machine.

will start by itself after it was shutoff for after
7-12 hours suddenly ? Why

try to change the water in the watertank with warm water, it shouldn`t be hot, but luke warm. Repeat the fill system routin a few times if necessary. If this doesn`t solve the problem, turn off the machine for half an hour or so, and then try again. Usually this is the solution for this problem; warmer water contains less oxygen and helps pushing the air out from the system easier.