2010 Mercedes Benz C 300 (204.054) V6-3.0L (272.947) Page 802

1051

Lambda control, before TWC left : Control implausible (P0173)

Test 1: Check self-adaptation.

Test 2: Possible cause:

- Lambda control

Affected functions:

- Engine output

1. Check self-adaptation.

Test 1.1: Check lambda control.

1.1. Check lambda control.

Test 1.1.1: Check signal from component B2/5 (Hot film mass air flow sensor) via actual value.

Test 1.1.2: Check seal of component B2/5 (Hot film mass air flow sensor) with air filter for cracks.

Test 1.1.3: Inspect air cleaner housing.

Test 1.1.4: Check component G3/3 (Left O2 sensor, before TWC [KAT]).

Test 1.1.5: Check component Y62 (Fuel injectors).

Test 1.1.6: Check exhaust system for leaks.

1.1.1. Check signal from component B2/5 (Hot film mass air flow sensor) via actual value.

Test 1.1.1.1: Check signal of component B2/5 (Hot film mass air flow sensor) via actual value with engine OFF.

Test 1.1.1.2: Check signal of component B2/5 (Hot film mass air flow sensor) via actual value with engine speed greater than 3500 rpm.

Test 1.1.1.3: Check reference signal of component B2/5 (Hot film mass air flow sensor).

1.1.1.1. Check signal of component B2/5 (Hot film mass air flow sensor) via actual value with engine OFF.

Warning!Communication with ECU required.

1.1.1.2. Check signal of component B2/5 (Hot film mass air flow sensor) via actual value with engine speed greater than 3500 rpm.

Warning!Communication with ECU required.

1.1.1.3. Check reference signal of component B2/5 (Hot film mass air flow sensor).

Test sequence

- Switch on ignition.

Status of relevant actual value:

- HFM-SFI ( Reference signal ):Warning! Communication with ECU required.

Specified value

- Reference signal[46...59] ms

Question

- Is the measurement value OK?

YES

The actual value is okay.End of test

NO

The actual value is not o.k.Possible cause and remedy