BMW DTC P0174 – System Too Lean (Bank 2)
DTC P0174 meaning on BMW
The DTC P0174 code on a BMW indicates that the engine control module (ECM) has detected a lean condition on Bank 2 of the engine. This means that there is an imbalance in the air-fuel mixture, with too much air or too little fuel being delivered to the cylinders on Bank 2.
BMW DTC P0174 symptoms
Symptoms of a DTC P0174 on a BMW may include:
- Check Engine Light (CEL) illuminated
- Decreased fuel efficiency
- Engine running rough or misfiring
- Loss of power or hesitation during acceleration
- Excessive exhaust emissions
BMW DTC P0174 causes
Common causes of a DTC P0174 on a BMW include:
- Vacuum leaks in the intake system
- Faulty oxygen sensors
- Dirty or clogged fuel injectors
- Fuel pump issues
- Mass airflow sensor (MAF) malfunction
BMW DTC P0174 seriousness
While a DTC P0174 may not cause immediate engine failure, it can lead to poor engine performance, reduced fuel efficiency, and increased emissions. Ignoring this code can potentially cause damage to other engine components over time.
How to diagnose DTC P0174 on BMW
To diagnose a DTC P0174 on a BMW, a mechanic may perform the following steps:
- Use a scan tool to retrieve the fault codes and freeze frame data
- Inspect the intake system for vacuum leaks
- Check the oxygen sensors for proper operation
- Clean or replace fuel injectors if necessary
- Test the fuel pump and MAF sensor
How to fix DTC P0174 on BMW
To fix a DTC P0174 on a BMW, the following steps may be taken:
- Repair any vacuum leaks in the intake system
- Replace faulty oxygen sensors
- Clean or replace clogged fuel injectors
- Address any fuel pump issues
- Clean or replace the MAF sensor
How to erase DTC P0174 on BMW
To erase a DTC P0174 on a BMW, the fault codes can be cleared using a scan tool. After the repairs have been made to address the underlying issue causing the lean condition, the codes can be cleared to reset the Check Engine Light and monitor the system for any recurring problems.
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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