2010 Mercedes Benz C 300 (204.054) V6-3.0L (272.947) Page 679

Test 1.2: Check signal lines on component B11/4 (Coolant temperature sensor).

Test 1.3: Check internal resistance of component B11/4 (Coolant temperature sensor).

1.1. Check component B11/4 (Coolant temperature sensor) using actual value.

Test prerequisite

- The actual value is not o.k.

Test sequence

- Switch on ignition.

Status of relevant actual value:

- Coolant temperature:Warning! Communication with ECU required.

- Coolant temperature sensor ( Signal voltage ):Warning! Communication with ECU required.

Specified values

- Voltage[20锟斤拷 C]: [3.45...3.32] V

- Voltage[30锟斤拷 C]: [2.93...2.82] V

- Voltage[40锟斤拷 C]: [2.41...2.32] V

- Voltage[50锟斤拷 C]: [1.93...1.86] V

- Voltage[60锟斤拷 C]: [1.51...1.46] V

- Voltage[70锟斤拷 C]: [1.18...1.13] V

- Voltage[80锟斤拷 C]: [0.90...0.87] V

- Voltage[90锟斤拷 C]: [0.70...0.67] V

- Voltage[100锟斤拷 C]: [0.54...0.25] V

- Voltage[110锟斤拷 C]: [0.42...0.40] V

Question

- Are the measurement values OK?

YES

The measurement values are OK.End of test

NO

The measurement values are not OK.Possible cause and remedy

- Line from component B11/4 (Coolant temperature sensor) to component N3/10 (ME-SFI [ME] control unit)

- B11/4 (Coolant temperature sensor)

End of test

1.2. Check signal lines on component B11/4 (Coolant temperature sensor).

Test sequence

- Switch on ignition.

Status of relevant actual value:

- Coolant temperature sensor ( Signal voltage ):Warning! Communication with ECU required.

Specified value

- If the connection is unplugged at component B11/4 (Coolant temperature sensor), the value is approx. 5 V.

- Bridge pin 1 in pin 2 at the unplugged connection of component B11/4 (Coolant temperature sensor).The value is< 0.5 V.

Question

- Is the actual value o.k.?

YES

The actual value is okay.Further possible causes of fault

- Check internal resistance of component B11/4 (Coolant temperature sensor).

NO

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

- Check lines from component B11/4 (Coolant temperature sensor) to component N3/10 (ME-SFI [ME] control unit).

End of test

1.3. Check internal resistance of component B11/4 (Coolant temperature sensor).