Question

What do the codes U1001 and U1000 mean on a 2004 Nissan Sentra 1.8L? Also, my check Engine light is on

Answer 1

Usually the problem is poor harness ground connection.

U1000 is a bad ground problem, you can clean the factory grounds with sand paper and tighen them back up. and you can also add a grounding kit to help the factory grounds.

 

U1000 NISSAN - CAN Communication Line - Signal Malfunction
- Controller Area Network (CAN) communication harness is open or shorted
- Faulty Engine Control Module (ECM)
 

 

Answer 2

U1000 Nissan Code - CAN Communication Line Signal Malfunction
Read more: https://www.autocodes.com/u1000_nissan.html

U1001 Nissan Code - Invalid or Missing Data for Primary Id
Read more: https://www.autocodes.com/u1001_nissan.html