Running lean

[SeanS]

Hi can anyone help my car is throwing on the EML with the code for running lean on bank 1. Also it sometimes has a slight misfire.
Do you how I can fix it?

[Steve Q]

Hi, this is the overview of your code error.
possible an air leak if the manifold has been removed or a leaking hose, i'd be checking all the hoses etc for tightness to start with then working from there for leaks .
if all ok then go to next items.
16555/P0171/000369 - Fuel Trim; Bank 1: System Too Lean
Possible Causes

• Mass Air Flow Sensor (G70) defective
• Intake System Leak(s)

Possible Solutions

• Check Mass Air Flow Sensor (G70)
• Check Fuel Pressure Regulation
• Check Fuel Pump
• Check Injectors
• Check Intake System for Leaks
• Check Exhaust System for Leaks
• Check Secondary Air System for Leaks
• Check Vacuum Pipes for Leaks

also this .
P0171 Audi Description
With the Air/Fuel Mixture Ratio Self-Learning Control, the actual mixture ratio can be brought closely to the theoretical mixture ratio based on the mixture ratio feedback signal from the heated oxygen sensors 1. The Engine Control Module (ECM) calculates the necessary compensation to correct the offset between the actual and the theoretical ratios.
In case the amount of the compensation value is extremely large (The actual mixture ratio is too lean.), the ECM judges the condition as the fuel injection system malfunction and light up the Malfunction Indicator Light (MIL) (2 trip detection logic).

IT may seem mad but has the MAF sensor plug been refitted properly, also worth a check just to eliminate connection issues.

[SeanS]

Wow thanks Steve looks I got some air leaks to check but glad it’s nothing major.

[Steve Q]

9 minutes ago, SeanS said:

Wow thanks Steve looks I got some air leaks to check but glad it’s nothing major.

You're welcome, glad I could help 🙂