U0078

Control Module Communication Bus F Off

Severity

🔴 High

Can you drive?

Limited driving only, diagnose soon

Approx. repair cost

$6–56 (est.)

Symptoms

Check Engine Light Is On
Incorrect operation of some vehicle systems
Lost connection with diagnostic equipment
Dashboard malfunctions
The car may go into emergency mode

Causes

Broken or damaged CAN bus wires
Oxidation or damage to connectors
Short circuit in CAN circuit
Malfunction of one of the control modules
Problems with module power supply

How to Fix

Check the integrity of the CAN bus wires
Inspect and clean all connectors
Check the module supply voltage
Diagnose each module separately
Replace damaged components

Related codes

U0079 U0080 U0100