BMW DTC P149B – EVAP System Shutoff Valve Control Circuit Low
DTC P149B meaning on BMW
The DTC P149B on a BMW indicates a fault with the EVAP (Evaporative Emission Control System) System Shutoff Valve Control Circuit being detected as low. This means that the control circuit for the EVAP system shutoff valve is not operating within the expected voltage range.
BMW DTC P149B symptoms
Symptoms of the DTC P149B on a BMW may include:
- Check Engine Light illuminated on the dashboard
- Decreased fuel efficiency
- Engine running rough or stalling
- Strong fuel odor near the vehicle
BMW DTC P149B causes
Common causes of the DTC P149B on a BMW include:
- Faulty EVAP system shutoff valve
- Wiring or connector issues in the control circuit
- ECU (Engine Control Unit) software or hardware problems
BMW DTC P149B seriousness
The DTC P149B should not be ignored as it can lead to increased emissions, reduced fuel efficiency, and potential drivability issues. While the vehicle may still be operable with this fault, it is recommended to address it promptly to prevent further damage to the EVAP system.
How to diagnose DTC P149B on BMW
To diagnose the DTC P149B on a BMW, a mechanic would typically perform the following steps:
- Use a diagnostic scanner to retrieve the fault code and freeze frame data
- Inspect the EVAP system shutoff valve and its wiring for any visible damage
- Check the voltage and continuity of the control circuit using a multimeter
- Perform a smoke test to check for leaks in the EVAP system
How to fix DTC P149B on BMW
To fix the DTC P149B on a BMW, the following steps may be taken:
- Replace the faulty EVAP system shutoff valve
- Repair any damaged wiring or connectors in the control circuit
- Update the ECU software if necessary
- Clear the fault code and perform a test drive to ensure the issue is resolved
How to erase DTC P149B on BMW
To erase the DTC P149B on a BMW, the fault code can be cleared using a diagnostic scanner. After the repair has been completed, the mechanic can reset the code, and the Check Engine Light should turn off if the issue has been successfully resolved.
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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