High Speed CAN Communication Bus (+) Low
2015-2015 Chevrolet Spark EV Electric Motor 🇩🇪
Description
The CAN High wire voltage is lower than expected, indicating a short to ground or excessive load on the bus.
Symptoms
- Communication failures
- Multiple DTCs from various modules
- Intermittent system operation
Common Causes
- CAN H wire shorted to ground
- Module pulling CAN H low
- Damaged wiring insulation
- Water intrusion in connector
Diagnostic Steps
- Measure CAN H voltage
- Disconnect modules one at a time to find short source
- Inspect wiring for chafing against ground
- Check connectors for moisture
Repair Notes
Find and repair the short to ground on the CAN H wire. Inspect for damaged insulation.
Related Codes
Other Network Codes
- U0001High Speed CAN Communication Bus
- U0002High Speed CAN Communication Bus Performance
- U0003High Speed CAN Communication Bus (+) Open
- 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
U0004 on Other Vehicles
Chevrolet Astro
1996-1996 4.3L V6 Vortec
Chevrolet Astro
1997-1997 4.3L V6 Vortec
Chevrolet Astro
1998-1998 4.3L V6 Vortec
Chevrolet Astro
1999-1999 4.3L V6 Vortec
Chevrolet Astro
2000-2000 4.3L V6 Vortec
Chevrolet Astro
2001-2001 4.3L V6 Vortec
Chevrolet Astro
2002-2002 4.3L V6 Vortec
Chevrolet Astro
2003-2003 4.3L V6 Vortec
Common Questions
What does code U0004 mean on a 2015-2015 Chevrolet Spark EV?
U0004 stands for "High Speed CAN Communication Bus (+) Low". The CAN High wire voltage is lower than expected, indicating a short to ground or excessive load on the bus.
What are the symptoms of U0004 on a Chevrolet Spark EV?
Common symptoms of U0004 include: Communication failures, Multiple DTCs from various modules, Intermittent system operation.
What causes U0004 on a 2015-2015 Chevrolet Spark EV?
Common causes of U0004 include: CAN H wire shorted to ground, Module pulling CAN H low, Damaged wiring insulation, Water intrusion in connector.
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