What usually causes it
- A damaged wire or a loose, rusty plug on the network line
- A weak battery or a bad ground
- A blown fuse for the engine computer
- A failed engine computer
U0100Starts at: Get it checked this week
Lost contact with the engine computer
Other computers in the car cannot talk to the engine computer. The engine computer runs the engine, so this can change how the car runs.
Check this first
Check that the battery cables are tight and clean, and look at the fuses for the engine computer. A weak battery can cause many network codes at once.
What to watch for
- The engine will not start or stalls
- Many warning lights on at once
- The car goes into a low power mode
Can I keep driving?
We rate U0100 as Get it checked this week. It is not an emergency yet, but it can get worse. If the light starts flashing, stop driving soon.
Quick answers about U0100
What does U0100 mean?
Lost contact with the engine computer. Other computers in the car cannot talk to the engine computer. The engine computer runs the engine, so this can change how the car runs.
Can I keep driving with U0100?
We rate U0100 as Get it checked this week. It is not an emergency yet, but it can get worse. If the light starts flashing, stop driving soon.
What usually causes U0100?
The most common causes, in order: A damaged wire or a loose, rusty plug on the network line; A weak battery or a bad ground; A blown fuse for the engine computer; A failed engine computer.
Estimates only. A mechanic should confirm. The same code can mean slightly different things on different cars; the app explains it for your exact year, make, model and mileage.