OBD Guide
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U240B

Radio Dedicated Bus Off

U240B is an OBD-II diagnostic trouble code meaning: Radio Dedicated Bus Off. Common causes: malfunction of the head unit (radio), problems with wiring or connectors. Estimated repair cost: $56–278.

Severity
⚠️ Medium
Can you drive?
Yes, but get it checked soon
Approx. repair cost
$56–278 (est.)

Symptoms

  • The standard audio system does not work or freezes
  • No sound from speakers
  • Steering wheel control buttons do not work
  • The head unit does not turn on
  • Error on the multimedia system display

Causes

  • Malfunction of the head unit (radio)
  • Problems with wiring or connectors
  • Short circuit in the circuit
  • Fault in other modules connected to the bus
  • Problems with radio power supply

How to Fix

  1. Check the power supply to the head unit
  2. Inspect the connectors and wiring of the radio system
  3. Carry out diagnostics of the head unit
  4. Update system software
  5. Check other modules connected to the bus

Related codes

U240AU240CU240D

FAQ

What does the U240B code mean?

U240B is an OBD-II diagnostic trouble code that indicates: Radio Dedicated Bus Off

What causes a U240B error code?

The most common causes of U240B include: Malfunction of the head unit (radio); Problems with wiring or connectors; Short circuit in the circuit; Fault in other modules connected to the bus.

How do I fix a U240B diagnostic trouble code?

To fix U240B: Check the power supply to the head unit. Inspect the connectors and wiring of the radio system. Carry out diagnostics of the head unit. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with U240B?

Yes, but get it checked soon

How much does it cost to fix U240B?

The estimated repair cost for U240B is $56–278. Actual cost depends on your vehicle, location, and labor rates.

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See also: Russian version · NationStat