High Speed CAN Communication Bus (+) Open
2000-2012 Mitsubishi Eclipse 2.4L I4
Description
The CAN High wire is open, disrupting high-speed bus communication. CAN H carries the dominant high signal.
Symptoms
- Multiple modules offline
- Warning lights illuminated
- Systems inoperative
- No scan tool communication on some modules
Common Causes
- Broken CAN H wire
- Corroded CAN H terminal
- Damaged CAN bus connector
- Wiring harness damage
Diagnostic Steps
- Measure voltage on CAN H (should be ~2.5V idle, ~3.5V dominant)
- Check continuity of CAN H wire
- Inspect CAN bus connectors
- Locate break using voltage drop test
Repair Notes
Locate and repair the open in the CAN H wire. Check all splice points.
Related Codes
Other Network Codes
- U0001High Speed CAN Communication Bus
- U0002High Speed CAN Communication Bus Performance
- U0004High Speed CAN Communication Bus (+) Low
- U0005High Speed CAN Communication Bus (+) High
- U0006High Speed CAN Communication Bus (-) Open
- U0007High Speed CAN Communication Bus (-) Low
- U0008High Speed CAN Communication Bus (-) High
- U0009High Speed CAN Communication Bus Shorted Together
- U0010Medium Speed CAN Communication Bus
- U0028Vehicle Communication Bus A Performance
U0003 on Other Vehicles
Mitsubishi 3000GT
1991-1999 3.0L V6
Mitsubishi 3000GT VR-4
1991-1999 3.0L Twin Turbo V6
Mitsubishi 3000GT VR-4
1991-1999 3.0L V6 Twin Turbo
Mitsubishi Colt JP
2002-2012 1.3L I4 4A90
Mitsubishi Colt JP
2002-2012 1.5L I4 4A91
Mitsubishi Delica D:5
2019-2025 2.2L I4 Turbo Diesel 4N14
Mitsubishi Diamante
1992-1996 3.0L V6
Mitsubishi Diamante
1997-2004 3.5L V6
Common Questions
What does code U0003 mean on a 2000-2012 Mitsubishi Eclipse?
U0003 stands for "High Speed CAN Communication Bus (+) Open". The CAN High wire is open, disrupting high-speed bus communication. CAN H carries the dominant high signal.
What are the symptoms of U0003 on a Mitsubishi Eclipse?
Common symptoms of U0003 include: Multiple modules offline, Warning lights illuminated, Systems inoperative, No scan tool communication on some modules.
What causes U0003 on a 2000-2012 Mitsubishi Eclipse?
Common causes of U0003 include: Broken CAN H wire, Corroded CAN H terminal, Damaged CAN bus connector, Wiring harness damage.