Error code U0155 is displayed and the check engine light is on - what does this mean?
The DTC U0155 indicates that there is a communication error between the vehicle's control unit and the instrument cluster. The OBD system recognizes that there is no or faulty data transmission via the CAN bus network. This EOBD fault code can occur with various manufacturers and affects the display functions in the cockpit.
What can cause this fault code?
- Defective instrument cluster control unit
- Damaged CAN bus cables between control units
- Loose or corroded plug connections on the instrument cluster
- Faulty ground connections in the vehicle network
- Faulty fuses for the communication system
- Software errors in the instrument cluster
- Overvoltage damage due to defective alternator
- Water damage to the instrument cluster
What symptoms occur in parallel with fault code U0155?
- Failed displays: Speedometer, rev counter or other instruments do not work
- Lighting problems: Cockpit backlighting fails
- Warning lights: Various indicator lights remain permanently on or off
- Missing information: On-board computer does not display data such as fuel consumption or range
- Starting problems: Vehicle may not start due to lack of communication
- Electronic malfunctions: Other control units also report communication errors
How can the problem with error code U0155 be rectified?
- The repair requires a systematic diagnosis of the communication network in the vehicle.
- Checking and replacing defective fuses for the instrument cluster and CAN bus system
- Cleaning and fixing all plug connections on the instrument cluster and applying contact spray
- Measuring the CAN bus lines with a multimeter and repairing damaged cables between the control units
- Replacement of the complete instrument cluster in the event of irreparable hardware defects
- Software update or reprogramming of the instrument cluster control unit via diagnostic device
- Checking and repairing the vehicle ground connections, especially on the dashboard
- Checking the vehicle electrical system voltage and repairing the alternator in the event of overvoltage or undervoltage
FAQ - Frequently asked questions about DTC U0155
Can I continue driving with fault code U0155?
It is possible to continue driving, but not recommended, as important vehicle information may be missing. If the instruments have failed, there is a safety risk as speed and warning messages are not displayed.
How much does it cost to repair error code U0155?
The repair costs vary depending on the cause: simple connector repairs cost 50-150 euros, while a new instrument cluster can cost 300-800 euros. Including labor, you should expect to pay 200-1200 euros.
Can trouble code U0155 be caused by a weak battery?
Yes, a weak or defective battery can cause communication problems. Low voltage impairs CAN bus communication and can trigger code U0155. A battery check should therefore be carried out.
How long does it take to diagnose error code U0155?
A professional diagnosis usually takes 1-2 hours. The technician must systematically check the CAN bus network and test various control units in order to localize the exact source of the fault.
Is the code U0155 manufacturer-specific or universal?
The DTC U0155 is a standardized OBD code that can occur with different manufacturers. However, the exact repair procedures may vary depending on the vehicle make and model.
Can I delete fault code U0155 myself?
Clearing is possible with an OBD diagnostic tool, but the code will return if the problem is not fixed. A professional repair of the cause is necessary for a permanent solution.