What does it mean?
U1113 is a Network (CAN bus, module communications) fault code. It indicates: Manufacturer-Specific CAN/Network Bus Fault . This is a standardised OBD-II code. The technical definition is the same regardless of the make or model of vehicle, although specific causes and symptoms can vary between vehicles.
Symptoms
- Several warning lamps illuminated at once with no single obvious failure
- Modules missing from the scan tool list or answering only intermittently
- Comfort, assistance or powertrain functions dropping out and returning
- Codes reappear soon after clearing, sometimes only when the vehicle is moving
- Unusual battery drain because the network cannot go to sleep
Likely causes
- Open circuit or short on one of the bus wires, frequently where the harness passes through a grommet or flexes
- Corroded, wet or loose connector on a shared network branch
- Module with a failing internal transceiver that disturbs traffic for every other unit
- Weak battery, bad ground or charging system noise causing modules to reset and drop off the bus
- Termination resistance out of specification after a module was removed or a harness was modified
- Aftermarket accessories spliced into the data lines
- Software or coding mismatch left after module replacement or programming
How to fix it
- Scan all modules, note which respond, and use the vehicle wiring layout to see which branch the silent modules share
- Check battery condition, charging voltage and main grounds before anything else
- Measure resistance across the CAN pair with power removed to confirm terminating resistors are intact
- Back-probe the bus lines and compare voltages against a known good branch, then wiggle test the harness
- Inspect connectors and splices on the suspect branch for water, corrosion and pin damage
- Disconnect modules one at a time to find a unit that is dragging the bus down
- Repair the wiring, then verify module software and coding, and replace a module only once it is proven faulty