BMW DTC P1491 – EGR Flow Insufficient Detected (Bank 2)
DTC P1491 meaning on BMW
The Diagnostic Trouble Code (DTC) P1491 for BMW indicates that the Engine Control Module (ECM) has detected insufficient flow in the Exhaust Gas Recirculation (EGR) system on Bank 2 of the engine. The EGR system is responsible for recirculating a portion of the engine’s exhaust gases back into the intake manifold to reduce combustion temperatures and lower harmful emissions.
BMW DTC P1491 symptoms
Symptoms of a DTC P1491 on a BMW may include:
- Check Engine Light (CEL) illuminated on the dashboard
- Reduced engine performance or power
- Increased fuel consumption
- Rough idling or stalling
BMW DTC P1491 causes
Common causes of a DTC P1491 on a BMW include:
- Clogged or restricted EGR passages
- Malfunctioning EGR valve
- Wiring or connector issues in the EGR system
- Exhaust gas leaks in the EGR system
BMW DTC P1491 seriousness
While a DTC P1491 may not cause immediate drivability issues, it can lead to increased emissions and potential long-term engine damage if left unresolved. It is important to address this issue promptly to ensure optimal engine performance and efficiency.
How to diagnose DTC P1491 on BMW
To diagnose a DTC P1491 on a BMW, a mechanic may perform the following steps:
- Use a diagnostic scanner to retrieve the fault code and freeze frame data
- Inspect the EGR system components for any signs of damage or blockages
- Check the EGR valve operation and wiring connections
- Perform a vacuum test on the EGR system to check for leaks
How to fix DTC P1491 on BMW
To fix a DTC P1491 on a BMW, the following steps may be taken:
- Clean or replace the EGR valve if it is found to be faulty
- Clean out any clogged EGR passages or tubes
- Repair any wiring or connector issues in the EGR system
- Address any exhaust leaks in the EGR system
How to erase DTC P1491 on BMW
After the underlying issue causing the DTC P1491 has been resolved, the fault code can be cleared using a diagnostic scanner. This will reset the Check Engine Light and erase the DTC from the ECM’s memory. Ensure that the repair has been successful before clearing the code to prevent it from reoccurring.
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
Some of the links on this page may be affiliate links, which means we may earn a small commission if you make a purchase. This helps us keep our DTC database up to date and provide valuable content for free. We only recommend products that we have tested and believe to be the best in their class.