Manufacturer Code Charts: 2070
B14 (Ambient temperature display temperature sensor) : Short circuit to ground (P0072)
Possible cause:
- B14 (Ambient temperature display temperature sensor)
Affected functions:
- Engine output
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Test 1: Ambient temperature
Test 2: Check component B14 (Ambient temperature display temperature sensor).
1. Ambient temperature
Preconditions for test Ambient temperature
Test prerequisite
- Air filter and associated hoses are correctly fitted.
Test sequence
- Drive vehicle with constant engine load at a speed of > 50 km/h (> 31 mph) for approx. 5 min.
Status of the relevant actual values:
- Ambient temperature:Warning! Communication with ECU required.
- Intake air temperature:Warning! Communication with ECU required.
Question
- Is the temperature difference between component B14 (Ambient temperature display temperature sensor) and component B17 (Intake air temperature sensor) greater than 40° C?
YES
Test 1.1: Check component B14 (Ambient temperature display temperature sensor).
Test 1.2: Check component B17 (Intake air temperature sensor).
1.1. Check component B14 (Ambient temperature display temperature sensor).
Test prerequisite
- Relevant fault codes exist or a complaint has been received.
Test sequence
- Detach coupling at component B14 (Ambient temperature display temperature sensor).
- Measure resistance with multimeter between pins (B14)1 and (B14) 2
Status of the relevant actual values:Specified value
- Temperature0° C:Resistor= [8.0...12.0] kohms
- Temperature10° C:Resistor= [4.5...7.0] kohms
- Temperature20° C:Resistor= [3.0...4.5] kohms
- Temperature30° C:Resistor= [2.0...3.0] kohms
- Temperature40° C:Resistor= [1.3...2.0] kohms
Question:Are the measurement values OK?
YES
The measurement values are OK.Possible cause and remedy
- Test wiring (N10/10) 3.3 - (B14) 2 for Short circuit or open circuit
- Test wiring (N10/10) 3.14 - (B14) 1 for Open circuit
- Component N10/10 (Driver-side SAM control module) is defective.
End of test
NO
The measurement values are not OK.Possible cause and remedy
- Component B14 (Ambient temperature display temperature sensor) is defective.
End of test
1.2. Check component B17 (Intake air temperature sensor).
Test 1.2.1: Check component B17 (Intake air temperature sensor) using actual value.
Test 1.2.2: Check plausibility of actual value B17 (Intake air temperature sensor) in control module ME 9.7 (AMG).
Test 1.2.3: Check internal resistance of component B17 (Intake air temperature sensor).
1.2.1. Check component B17 (Intake air temperature sensor) using actual value.
Test sequence
- Switch on ignition.
Status of relevant actual value:
- Intake air temperature:Warning! Communication with ECU required.
Specified value
- Current temperature in area surrounding component B17 (Intake air temperature sensor)
Question
- Is the actual value o.k.?
YES
The actual value is okay.End of test
NO
The actual value is not o.k.Possible cause and remedy
- Check plausibility of actual value B17 (Intake air temperature sensor) in control module N3/10 (ME-SFI [ME] control unit).
- Check internal resistance of component B17 (Intake air temperature sensor).
1.2.2. Check plausibility of actual value B17 (Intake air temperature sensor) in control module ME 9.7 (AMG).
Test prerequisite
- The actual value is not o.k.
Test sequence
- Detach coupling at component B17 (Intake air temperature sensor).
- Switch on ignition.
Status of relevant actual value:
- Intake air temperature:Warning! Communication with ECU required.
Specified value
- If the connector is unplugged at component B17 (Intake air temperature sensor), value [ -40° C ] is displayed.
- Bridge pin 1 in pin 2 at the unplugged connection of component B17 (Intake air temperature sensor).The value is approx. [ 150° C ] for a short period of time and drops back down to the substitute value of approx. [ -40° C ].
Question
- Is the actual value o.k.?
YES
The actual value is okay.Further possible causes of fault
- Check internal resistance of component B17 (Intake air temperature sensor).
NO
The actual value is not o.k.Possible cause and remedy
- Signal wire
End of test
1.2.3. Check internal resistance of component B17 (Intake air temperature sensor).
Test sequence
- Switch off ignition.
- Detach coupling at component B17 (Intake air temperature sensor).
- Measure resistance with multimeter between pins (B17) 1 and (B17) 2
Specified value
- Resistor(20° C): [2350...2500]ohms
- Resistor(30° C): [1600...1700]ohms
- Resistor(40° C): [1100...1200]ohms
- Resistor(50° C): [800...900]ohms
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
- B17 (Intake air temperature sensor)
End of test
NO
Ambient temperature
The temperature difference is not greater than 40 °C.End of test
2. Check component B14 (Ambient temperature display temperature sensor).
Test 2.1: Check component B14 (Ambient temperature display temperature sensor).
2.1. Check component B14 (Ambient temperature display temperature sensor).
Test prerequisite
- Relevant fault codes exist or a complaint has been received.
Test sequence
- Detach coupling at component B14 (Ambient temperature display temperature sensor).
- Measure resistance with multimeter between pins (B14)1 and (B14) 2
Status of the relevant actual values:Specified value
- Temperature0° C:Resistor= [8.0...12.0] kohms
- Temperature10° C:Resistor= [4.5...7.0] kohms
- Temperature20° C:Resistor= [3.0...4.5] kohms
- Temperature30° C:Resistor= [2.0...3.0] kohms
- Temperature40° C:Resistor= [1.3...2.0] kohms
Question:Are the measurement values OK?
YES
The measurement values are OK.Possible cause and remedy
- Test wiring (N10/10) 3.3 - (B14) 2 for Short circuit or open circuit
- Test wiring (N10/10) 3.14 - (B14) 1 for Open circuit
- Component N10/10 (Driver-side SAM control module) is defective.
End of test
NO
The measurement values are not OK.Possible cause and remedy
- Component B14 (Ambient temperature display temperature sensor) is defective.
End of test