Audi P1177: O2 Correction Behind Catalyst B2 Limit Attained

Is your scanner showing Audi P1177?
No worries. We'll show you what it means and how to deal with it.

Presented by

Randy Worner

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Audi P1177: O2 Correction Behind Catalyst B2 Limit Attained

OVERVIEW

Severity

High

DIY Difficulty Level

Intermediate

Repair Cost

$100-$300

Can I Still Drive?

Yes (Short-term only)

What Does The Audi P1177 Code Mean?

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, the coolant temperature must be at least 80 degrees Celsius, and the oxygen sensor heater for oxygen sensor before the catalytic converter must be properly functioning. The ECM has detected a malfunction of the oxygen sensor.

Note:

Vacuum in the intake system sucks in the leak detection spray with false air. Leak detection spray decreases ignition quality of the fuel mixture. This causes a drop in engine speed and changes the value produced by the Heated Oxygen Sensor (HO2S).
Vehicle must be raised before connector for oxygen sensor is accessible.
The oxygen sensor before catalytic converter has a static regulation and can be differentiated from the oxygen sensor behind catalytic converter via a 6-pin connector.