<!-- from fixya rte -->Check engine light code u1000 - 2005 Nissan Maxima

no country told. this code is vary serious , it mean the CAN_BUS network can not communicate and most things on it now fail. (lots)
get the car serviced
or DIY buy the service manual
2 choices.
gue$$ing be costly
look for harness damage, from past collision or even, rodent damage eating wires. under hood.


U1000 CAN Communication Line - Signal Malfunction

no car stated ,no year, no engine.stated. (what a challenge no?)

:

This is a communication code. One or more computer modules are not communicating with the main computer. Reset the code and see if it returns. Often these codes are set due to a low battery condition. If the code returns it may be tricky to diagnose as it will most likely be an electrical/wiring issue

Hi Corky, Have you checked for injection? It sounds to me as if there's a problem with the anti theft system. Regards John

Does the scanner give you any other read outs ?

Stuck or faulty variable cam timing solenoid

That is an emisions code I believe

U1000 = Loss of Communication with PCM

One missed communication code isn't normally something you should worry about. The modules in the system pass State of Health messages back and forth on a continual basis. Some times these messages are missed due to electrical noise or other factors in the system. The next time the message is sent it may be received just fine but the previous code is not reset. If you see a lot of these codes then you need to start thinking of battery or data link problems.

u 1000 is a communication fault code

sometimes coming data,but the every error comunication,for the scannner
rpm up and down same the lightgauge,low high,codes u 1001 1000