Error code
OBD2 U0073
OBD2U0073
Diagnostic Trouble Code· Standard OBD-II fault code read from the vehicle's onboard diagnostics.
What it means
Control Module Communication Bus Off.
Severity
severeDriving may be unsafe due to erratic system behavior; should not drive until the issue is resolved.
Summary
U0073 indicates that there is an issue with communication between control modules on the data bus network in your vehicle.
Symptoms
- Check Engine light may be on
- Instrument panel cluster warning lamps may illuminate
- Transmission may not shift or defaults to 2nd gear
- Door locks may cycle by themselves
- Engine may not crank intermittently
- Driver information center (DIC) message is displayed
- Cluster gauges may operate erratically
- Applying the brakes may cause cluster to function erratically and unwarranted chimes to sound
Common Causes
- Terminal pins have backed out at module connector
- Module's electrical connector not fully seated
- CANbus open or shorted to ground
- Corrosion in control module connectors
- Intermittent or poor connections in circuit connectors
- Data link resistor is open or shorted
- Water in various control module connectors
- Shorted control module
Diagnosis
- Plug a scan tool into the data link connector port and attempt to read codes.
- Check for proper resistance at the Data Link Connector (DLC).
- Perform a wiggle test on CANbus wires to find breaks or loose connections.
- Inspect connectors for water or corrosion, clean and apply dielectric grease as needed.
- Unplug each module on the circuit to check for faulty modules.
Fixes
FAQ
How can I diagnose U0073?
Use a digital volt-ohmmeter (DVOM) and detailed wiring diagrams to check for proper resistance, breaks in wires, loose connections, corrosion, or faulty modules.
Not affiliated with OBD2. Answer summarized from the manufacturer's manual linked above; consult that source for the authoritative procedure.
More OBD2 codes
- U0001High Speed CAN Communication Bus
- U0002High Speed CAN Communication Bus (Performance)
- U0003High Speed CAN Communication Bus (Open)
- U0004High Speed CAN Communication Bus (Low)
- 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 to Bus)
- U0010Medium Speed CAN Communication Bus
- U0011Medium Speed CAN Communication Bus (Performance)
- U0012Medium Speed CAN Communication Bus (Open)