U0073critical severityNetwork
Control Module Communication Bus A Off
on 2008 Audi R8 4.2L V8 · AWD
What this code means
CAN bus A is not communicating. Complete loss of communication on the primary bus.
Symptoms
- Multiple systems down
- Multiple warning lights
- Vehicle may not start
- No scan tool communication
Common causes
- CAN bus wiring shorted or open
- Termination resistor failure
- Module failure shorting the bus
- Major wiring harness damage
Diagnostic steps
- Check CAN bus voltage levels
- Measure bus resistance
- Isolate bus segments
- Check for physical damage to wiring
Repair notes
Major network failure. Systematic diagnosis required.
🔌 Don't have a code reader?
Any of these will read and clear this code — pick by how deep you want to go.
Bluetooth code reader (~$25)
Veepeak OBDCheck BLE →
Pairs with your phone — reads and clears codes, live data.
Serious DIY (~$100)
BlueDriver Pro →
Enhanced codes (ABS, airbag, TPMS) plus repair reports.
Shop-grade tablet (~$300+)
Autel MaxiCOM MK808S →
Bidirectional tests, service resets, all systems.
As an Amazon Associate, OLP earns from qualifying purchases — how we link. This never changes the specs we publish.
Other Network codes on this vehicle
00003
Control Module - Defective
01304
Radio - No Communication
01312
Powertrain Data Bus - Defective
01314
Engine Control Module (ECM) - no communications
01315
Transmission Control Module (TCM) - No Communication
01316
ABS Control Module - No Communication
01317
Instrument Cluster Control Module (J285) - No Communication
01318
Immobilizer Control Module - No Communication
01321
Airbag Control Module - No Communication
U0001
High Speed CAN Communication Bus