ME9.7

The signal of the oxygen sensor upstream of the catalytic converter of the left cylinder bank is shifted towards 'Rich'. (P2A03)


Possible cause:

- G3/3 (Left O2 sensor, before TWC [KAT])
- Selfadaptation of mixture formation
Affected functions:

- Engine diagnosis
- Exhaust system

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Test 1: Check exhaust system for leaks.

Test 2: Check self-adaptation of mixture formation.

Test 3: Check component G3/3 (Left O2 sensor, before TWC [KAT]).

1. Check exhaust system for leaks.
Possible cause of fault

- Leakage on catalytic converter at flange connection to exhaust manifold and in area of O2 sensor
Possible remedy

- Check O2 sensor for correct seating, tightening torque and leaktightness.
- Check weld seams on catalytic converter for leaktightness.
End of test

2. Check self-adaptation of mixture formation.
Test sequence

- Check actual value Selfadaptation of mixture formation.
- Carry out the following tests.
Continue with button F2

Warning!Communication with ECU required.


3. Check component G3/3 (Left O2 sensor, before TWC [KAT]).
Warning!Communication with ECU required.