P0494 – BMW DTC

BMW DTC P0494 – Fan Speed Low

DTC P0494 meaning on BMW

The Diagnostic Trouble Code (DTC) P0494 for BMW indicates that the engine control module (ECM) has detected a low fan speed signal from the secondary air injection (AIR) system. This code is specific to BMW vehicles and is related to the operation of the secondary air injection system.

BMW DTC P0494 symptoms

Symptoms of DTC P0494 on a BMW may include:

• Check Engine Light (CEL) illuminated on the dashboard
• Reduced engine performance
• Possible rough idling or stalling

BMW DTC P0494 causes

Common causes of DTC P0494 on a BMW include:

• Defective secondary air injection pump
• Faulty secondary air injection pump relay
• Wiring or connection issues in the secondary air injection system

BMW DTC P0494 seriousness

While DTC P0494 may not cause immediate drivability issues, it is important to address this code promptly to prevent potential damage to the secondary air injection system and ensure optimal engine performance.

How to diagnose DTC P0494 on BMW

To diagnose DTC P0494 on a BMW, you can perform the following steps:

1. Use a diagnostic scanner to retrieve the fault codes stored in the ECM
2. Inspect the secondary air injection pump and related components for any visible damage or defects
3. Check the secondary air injection pump relay for proper operation
4. Test the wiring and connections in the secondary air injection system for continuity and proper voltage

How to fix DTC P0494 on BMW

To fix DTC P0494 on a BMW, you may need to:

1. Replace the faulty secondary air injection pump if it is determined to be the cause
2. Replace the defective secondary air injection pump relay
3. Repair any damaged wiring or connections in the secondary air injection system
4. Clear the fault codes from the ECM after completing the repairs

How to erase DTC P0494 on BMW

To erase DTC P0494 on a BMW, you can use a diagnostic scanner to clear the fault codes stored in the ECM. After addressing the underlying issue causing the code and making the necessary repairs, clearing the fault codes will reset the Check Engine Light and ensure that the system is functioning properly.

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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