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Home/DTC Codes/Fiat/Cronos/2018-2025 1.3L I4 Flex Firefly/B0421
B0421

ABS Warning Lamp Circuit

2018-2025 Fiat Cronos 1.3L I4 Flex Firefly

Moderate SeverityBodyGeneric (SAE)

Description

Malfunction in the ABS warning lamp circuit. The lamp may not illuminate or may stay on incorrectly.

Symptoms

  • ABS light does not come on during bulb check
  • ABS light always on
  • Cannot determine ABS system status
  • Light flickering

Common Causes

  • Burnt out lamp
  • Cluster fault
  • ABS module lamp driver failure
  • Wiring issue

Diagnostic Steps

  1. Check lamp during key-on bulb check
  2. Scan ABS module for codes
  3. Test lamp drive circuit
  4. Inspect wiring from ABS module to cluster

Repair Notes

Replace ABS warning lamp or repair wiring circuit.

Related Codes

B0400Instrument Cluster General MalfunctionB0420Check Engine Lamp Circuit

Other Body Codes

B0421 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 B0421 mean on a 2018-2025 Fiat Cronos?

B0421 stands for "ABS Warning Lamp Circuit". Malfunction in the ABS warning lamp circuit. The lamp may not illuminate or may stay on incorrectly.

What are the symptoms of B0421 on a Fiat Cronos?

Common symptoms of B0421 include: ABS light does not come on during bulb check, ABS light always on, Cannot determine ABS system status, Light flickering.

What causes B0421 on a 2018-2025 Fiat Cronos?

Common causes of B0421 include: Burnt out lamp, Cluster fault, ABS module lamp driver failure, Wiring issue.

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