Hello, I have a 100er(C4) that does not come through the AU because the oxygen content in the exhaust gas is too high and that is only idle. Should according to the examiner be 1.0%, however, is about 1.33%. He also thinks that after pumping at the brake and thus changing the oxygen concentration over the brake power amplifier, the regulation should have brought the oxygen content back to normal, but what it did not do. What can it be about? The Lambda probe is two years ago If it were to affect the regulation, it would have to be defective over the total speed spectrum.