P3421 – BMW DTC

BMW DTC P3421 – Cylinder 3 Exhaust Valve Control Circuit/Open

DTC P3421 meaning on BMW

The Diagnostic Trouble Code (DTC) P3421 for BMW indicates a fault in the Cylinder 3 Exhaust Valve Control Circuit, specifically an open circuit. This means that there is an interruption in the electrical connection that controls the exhaust valve in cylinder 3 of the engine.

BMW DTC P3421 symptoms

Symptoms of DTC P3421 on a BMW may include:

• Check Engine Light (MIL) illuminated on the dashboard
• Engine running rough or misfiring
• Reduced engine performance
• In some cases, the vehicle may go into a limp mode

BMW DTC P3421 causes

The common causes of DTC P3421 on a BMW include:

• Faulty exhaust valve control solenoid
• Open or short circuit in the wiring harness related to the exhaust valve control circuit
• Faulty Engine Control Module (ECM)

BMW DTC P3421 seriousness

DTC P3421 should not be ignored as it can lead to engine performance issues and potential damage if left unresolved. It is recommended to address this issue promptly to prevent further complications.

How to diagnose DTC P3421 on BMW

To diagnose DTC P3421 on a BMW, you can follow these steps:

1. Use a diagnostic scanner to retrieve the fault codes and identify P3421.
2. Inspect the wiring harness connected to the exhaust valve control circuit for any visible damage or loose connections.
3. Test the exhaust valve control solenoid for proper operation.
4. If necessary, perform a continuity test on the wiring to check for any open or short circuits.

How to fix DTC P3421 on BMW

To fix DTC P3421 on a BMW, you can consider the following steps:

1. Replace the faulty exhaust valve control solenoid if it is found to be defective.
2. Repair any damaged wiring or connectors in the exhaust valve control circuit.
3. If the issue persists, consider testing and potentially replacing the Engine Control Module (ECM).

How to erase DTC P3421 on BMW

To erase DTC P3421 on a BMW after the issue has been resolved, you can:

1. Use a diagnostic scanner to clear the fault codes stored in the ECM memory.
2. Ensure that the repair has been completed successfully before clearing the codes.
3. Once the codes are cleared, monitor the vehicle for any recurrence of the fault code.

Recommended tools & DTC Scanners for BMW

Best Diagnostic App for modern BMWs: BimmerLink

Recommended Bluetooth adapter for Bimmerlink: OBDLink CX

Cable adapter for Bimmerlink: Enet Cable USB Type C

For older BMWs we recommend: Autel AutoLink AL319 (2024 version)

Easy-to-use Multimeter for reliable diagnostics: AstroAI Auto-ranging Multimeter

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