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Auto ... 2/26/2018

2014 BMW 550i GT Base 8 Cyl 4.40L


How do I diagnose P2177 OBD-II Trouble Code of a car? Is there any issue with System Too Lean off Idle Bank 1?

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PartsAvatar Ca

PartsAvatar Ca 2/26/2018

What the P2177 code means?

The P2177 code means that the system is too lean off idle for bank 1. What that tells us is that the air-fuel mixture is too lean for the bank 1 half of the engine. The engine control module (ECM) constantly monitors the air-fuel ratio, and when it is found to be too lean off idle for bank 1, the Check Engine Light is set, which can be seen on the dashboard. With the Check Engine Light, a failsafe mode is set. This failsafe mode is enabled to protect the engine from damage and sets a fixed air-fuel ratio to prevent the vehicle from becoming too rich or too lean. The failsafe mode will remain on until normal operation is detected or the code is repaired.

What causes the P2177 code?

Faulty air/fuel ratio sensor/oxygen sensor
Faulty mass airflow sensor
Rarely - faulty Power train Control Module

What are the symptoms of the P2177 code?

Symptoms can include just a service engine soon lamp, poor acceleration, a hesitation or misfire upon acceleration or at start up, engine stall at start up, or there may be no symptoms at all. Some code setting conditions can lead to engine and/or catalytic converter damage if left unattended over a long period of time.

Common mistakes when diagnosing the P2177 code:

Technicians report that this code rarely occurs without the accompaniment of other fuel system codes. This code is rarely exhibited in vehicles that are not manufactured in Europe and Japan. Failure to diagnose other codes, before diagnosing this code, can lead to a misdiagnosis.

What repairs can fix the P2177 code?

1. Fuel injectors replaced or unclogged
2. Fuel delivery issues or low fuel pressure resolved
3. Mass air flow sensor replaced or cleaned as needed
4. Oxygen sensors replaced
5. Air intake leaks repaired
6. Cause of engine misfires repaired


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