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Home/DTC Codes/Fiat/Cronos/2018-2025 1.3L I4 Flex Firefly/U0046
U0046

Vehicle Communication Bus B Off

2018-2025 Fiat Cronos 1.3L I4 Flex Firefly

High SeverityNetworkGeneric (SAE)

Description

CAN bus B is completely offline. No communication on the secondary CAN bus.

Symptoms

  • Secondary systems inoperative
  • Body control functions down
  • Climate control offline
  • Entertainment system not communicating

Common Causes

  • CAN bus B wiring shorted or open
  • Bus B termination resistor failure
  • Module pulling down bus B
  • Major connector failure

Diagnostic Steps

  1. Measure bus B resistance
  2. Check bus B voltage levels
  3. Isolate bus B segments
  4. Inspect bus B connectors

Repair Notes

Complete bus B failure requires systematic wiring diagnosis.

Related Codes

U0010Medium Speed CAN Communication BusU0073Control Module Communication Bus A Off

Other Network Codes

U0046 on Other Vehicles

Fiat 124 Spider

2017-2020 1.4L I4 Turbo

Fiat 126p Maluch

1973-2000 0.65L I2 Air-Cooled

Fiat 126p Maluch

1987-2000 0.7L I2 Air-Cooled

Fiat 500

2012-2019 1.4L I4

Fiat 500 Abarth

2012-2019 1.4L I4 Turbo

Fiat 500 BR

2011-2020 1.4L I4 Flex Fire Evo

Fiat 500 PL

2007-2025 1.0L I3 Hybrid FireFly 70

Fiat 500 PL

2007-2025 1.2L I4 Fire 69

Common Questions

What does code U0046 mean on a 2018-2025 Fiat Cronos?

U0046 stands for "Vehicle Communication Bus B Off". CAN bus B is completely offline. No communication on the secondary CAN bus.

What are the symptoms of U0046 on a Fiat Cronos?

Common symptoms of U0046 include: Secondary systems inoperative, Body control functions down, Climate control offline, Entertainment system not communicating.

What causes U0046 on a 2018-2025 Fiat Cronos?

Common causes of U0046 include: CAN bus B wiring shorted or open, Bus B termination resistor failure, Module pulling down bus B, Major connector failure.

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