U0028moderate severityNetwork
Vehicle Communication Bus A Performance
on 2014 Ram 2500 6.7L I6 Cummins Diesel · 4WD
What this code means
CAN bus A is communicating but performance is below acceptable threshold. Data is being lost or corrupted.
Symptoms
- Intermittent warning lights
- Occasional system glitches
- Delayed module responses
- Scan tool slow or intermittent
Common causes
- High bus load from chatty module
- Degraded wiring causing retransmissions
- Poor termination
- Electromagnetic interference from aftermarket equipment
Diagnostic steps
- Monitor CAN bus load percentage
- Check bus termination resistance
- Scope bus signals for noise
- Remove aftermarket devices and retest
- Check for proper wire twist rate on CAN pair
Repair notes
Reduce bus load or repair wiring quality issues. Ensure proper bus termination.
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Other Network codes on this vehicle
U0001
High Speed CAN Communication Bus
U0002
High Speed CAN Communication Bus Performance
U0003
High Speed CAN Communication Bus (+) Open
U0004
High Speed CAN Communication Bus (+) Low
U0005
High Speed CAN Communication Bus (+) High
U0006
High Speed CAN Communication Bus (-) Open
U0007
High Speed CAN Communication Bus (-) Low
U0008
High Speed CAN Communication Bus (-) High
U0009
High Speed CAN Communication Bus Shorted Together
U0010
Medium Speed CAN Communication Bus