Network
generic / SAE
U0004
High Speed CAN Communication Bus (+) Low
The CAN-High signal stays below its valid voltage window. Common cause is a short to ground on the CAN-H wire or a transceiver that pulls the line down. The bus stops working until the offending node is isolated.
SystemNetwork
Typegeneric / SAE
GroupU0
Range / number– / 04
Possible causes
- CAN-High shorted to ground high
- Internal transceiver failure on a node medium
- Gateway module routing CAN messages incorrectly low
Symptoms
- Multiple warning lights may illuminate
- Affected modules may go into limp mode or shut down
- Specific functions inoperative depending on module
- Diagnostic tools may show communication faults
Inspection / repair
- Difficulty: hard
- DIY: shop recommended
- Estimated cost: 80–700 €
- Estimated time: 1–5 h
- Component: can high wire
- Component: can transceiver
- MIL / check engine light
- limp mode possible
Sources
References
sae:J2012
iso:11898