DTC P1128 Audi

Long Term Fuel Trim Add. Air. Bank 1 System Too Lean

Long Term Fuel Trim Add. Air. Bank 1 System Too Lean

Description

Engine started, battery voltage must be at least 11.5v, all electrical components must be off, the ground between the engine and the chassis must be well connected, the exhaust system must be properly sealed between the catalytic converter and the cylinder head, and the oxygen sensor heater for oxygen sensor before the catalytic converter must be properly functioning. The fuel mixture is so rich that the O2S control is on lean limit. Note: When an O2S malfunction (P0131 to P0414) is also stored with this malfunction, the O2S malfunction(s) should be repaired first. Note: After exhaust system repairs, make sure exhaust system is not under stress and that it has sufficient clearance from the bodywork. If necessary, loosen double clamps and align exhaust pipe so that sufficient clearance is maintained to the bodywork and support rings carry uniform loads. Do not use any silicone sealant. Traces of silicone components which are sucked into the engine are not burned there, and they damage the oxygen sensor.

Cause and Solution

Fuel pressure is too low or fuel quantity supplied is too low
Fuel filter faulty
Transfer fuel pump has failed
Fuel injector is faulty (sticking or not opening)
Engine speed (RPM) sensor is faulty
MAF sensor circuit open
MAF sensor circuit shorted to ground
Air leak in the manifold
Secondary air injection system combi-valve stuck open
Secondary air injection system electrical short

Video Guide

Duration: PT5M2S | Uploaded: 2020-06-20

Diagnostic Info

  • DTC Code: P1128
  • Brand: Audi
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