P1549 – BMW DTC

BMW DTC P1549 – Idle Air Control System RPM Higher Than Expected (Bank 2)

DTC P1549 meaning on BMW

DTC P1549 on a BMW indicates that the Idle Air Control (IAC) system on Bank 2 is detecting an RPM higher than expected. The IAC system is responsible for controlling the engine idle speed by regulating the amount of air entering the engine.

BMW DTC P1549 symptoms

Symptoms of DTC P1549 on a BMW may include:

• High idle speed
• Engine stalling at idle
• Decreased fuel efficiency
• Check Engine Light illuminated

BMW DTC P1549 causes

Common causes of DTC P1549 on a BMW include:

• Faulty Idle Air Control (IAC) valve
• Vacuum leaks in the intake system
• Dirty or clogged throttle body
• Issues with the engine control module (ECM)

BMW DTC P1549 seriousness

While DTC P1549 may not cause immediate drivability issues, it can lead to poor engine performance and decreased fuel efficiency if left unresolved. It is recommended to address this issue promptly to prevent further damage to the engine components.

How to diagnose DTC P1549 on BMW

To diagnose DTC P1549 on a BMW, a mechanic may perform the following steps:

1. Use a diagnostic scanner to retrieve the fault code and freeze frame data
2. Inspect the Idle Air Control (IAC) valve for proper operation
3. Check for vacuum leaks in the intake system
4. Clean the throttle body to ensure smooth airflow
5. Test the engine control module (ECM) for any faults

How to fix DTC P1549 on BMW

To fix DTC P1549 on a BMW, the following steps may be taken:

1. Replace the faulty Idle Air Control (IAC) valve
2. Repair any vacuum leaks in the intake system
3. Clean the throttle body to remove any deposits
4. Reset the engine control module (ECM) and perform an idle relearn procedure

How to erase DTC P1549 on BMW

To erase DTC P1549 on a BMW, the fault code can be cleared using a diagnostic scanner. After addressing the underlying issue causing the fault code, the code can be cleared to reset the Check Engine Light and monitor the system for any recurring issues.

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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