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Home/DTC Codes/Porsche/Boxster/2000-2004 2.7L H6/B0421
B0421

ABS Warning Lamp Circuit

2000-2004 Porsche Boxster 2.7L H6

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

Porsche 718 Boxster

2017-2024 2.0L H4 Turbo

Porsche 718 Boxster

2017-2024 2.0L Turbo H4

Porsche 718 Boxster GTS

2020-2024 4.0L H6

Porsche 718 Boxster S

2017-2024 2.5L Turbo H4

Porsche 718 Cayman

2017-2024 2.0L H4 Turbo

Porsche 718 Cayman

2017-2024 2.0L Turbo H4

Porsche 718 Cayman GT4

2019-2024 4.0L H6

Porsche 718 Cayman GTS

2020-2024 4.0L H6

Common Questions

What does code B0421 mean on a 2000-2004 Porsche Boxster?

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 Porsche Boxster?

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 2000-2004 Porsche Boxster?

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

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