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Manufacturer Code Charts: 2070


Component B14 (Ambient temperature display temperature sensor) has a short circuit to ground. (P0072)


Possible cause:

- B14 (Ambient temperature display temperature sensor)
Affected functions:

- Power generation

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Test 1: Ambient temperature

Test 2: Check component B14 (Ambient temperature display temperature sensor).

1. Ambient temperature

Test 1.1: Check component B14 (Ambient temperature display temperature sensor).

Test 1.2: Check component B2/5b1 (Intake air temperature sensor).

1.1. Check component B14 (Ambient temperature display temperature sensor).
Test prerequisites

- The power supply of component N10/1 (Driver-side SAM control unit with fuse and relay module) is OK.
- Fault code 9063 is current, and (or) at least one of the relevant actual values is not OK.
Test sequence

- Detach coupling at component B14 (Ambient temperature display temperature sensor).
- Connect resistance simulator to the connector of component B14 (Ambient temperature display temperature sensor).
- Connect resistance substitution unit between sockets (B14)1 and (B14) 2
- Adjust resistance values one after another and compare them with the actual value.
Status of relevant actual value:
- B14 (Ambient temperature display temperature sensor):Warning! Communication with ECU required.
Specified value

- Resistor9.6 kohms:Temperature: [0° C]
- Resistor5.9 kohms:Temperature: [10° C]
- Resistor3.7 kohms:Temperature: [20° C]
- Resistor2.4 kohms:Temperature: [30° C]
- Resistor1.6 kohms:Temperature: [40° C]
Question:Is the actual value o.k.?







YES
The actual value is okay.Possible cause and remedy

- Component B14 (Ambient temperature display temperature sensor) is defective.
End of test







NO
The actual value is not o.k.Possible cause and remedy

- Check lines from B14 (Ambient temperature display temperature sensor) to N10/1 (Driver-side SAM control unit with fuse and relay module) for Short circuit or open circuit.
- Component N10/1 (Driver-side SAM control unit with fuse and relay module) is defective.
End of test







1.2. Check component B2/5b1 (Intake air temperature sensor).

Test 1.2.1: Check component B2/5b1 (Intake air temperature sensor) using actual value.

Test 1.2.2: Check plausibility of actual value B2/5b1 (Intake air temperature sensor) in control module ME 9.7.

Test 1.2.3: Check internal resistance of component B2/5b1 (Intake air temperature sensor).

1.2.1. Check component B2/5b1 (Intake air temperature sensor) using actual value.
Test prerequisites

- Switch off ignition.
- Leave vehicle with engine hood open for > 12 h.
Note

- The test prerequisites must be fulfilled for the test result to be meaningful.


Test sequence

- Switch on ignition.
Status of relevant actual value:
- Intake air temperature:Warning! Communication with ECU required.
- Ambient temperature:Warning! Communication with ECU required.
Specified value

- The intake air temperature may be max. 5° C below the ambient temperature or 15° C above the ambient temperature.
Question

- Is the actual value for intake air temperature OK?


YES
The actual value is okay.Further procedure

- If only fault codes 1599 and 1600 occur in control unit ME-SFI, erase the fault memory.
- The component may not be replaced.
End of test

NO
The actual value is not o.k.Possible cause and remedy

- Check plausibility of actual value B2/5b1 (Intake air temperature sensor) in control module N3/10 (ME-SFI [ME] control unit).
- Check internal resistance of component B2/5b1 (Intake air temperature sensor).


1.2.2. Check plausibility of actual value B2/5b1 (Intake air temperature sensor) in control module ME 9.7.
Image legends

- Picture1
- B2/5 (Hot film mass air flow sensor)
- Connector (5-pin)
- Picture2
- B2/5 (Hot film mass air flow sensor)
- Connector (4-pin)
Test prerequisite

- The actual value is not o.k.
Test sequence

- Detach coupling at component B2/5 (Hot film mass air flow 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 B2/5b1 (Intake air temperature sensor), value [ -40° C ] is displayed.
- Bridge pin 2 in pin 3 at the unplugged connection of component B2/5b1 (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 B2/5b1 (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 B2/5b1 (Intake air temperature sensor).
Test sequence

- Switch off ignition.
- Detach coupling at component B2/5 (Hot film mass air flow sensor).
- Measure resistance with multimeter between pins (B2/5) 2 and (B2/5) 3
Specified value

- Resistor(0° C): [5100...5900]ohms
- Resistor(5° C): [4100...4800]ohms
- Resistor(10° C): [3300...3900]ohms
- Resistor(15° C): [2700...3200]ohms
- Resistor(20° C): [2350...2500]ohms
- Resistor(25° C): [1900...2100]ohms
- Resistor(30° C): [1600...1700]ohms
- Resistor(35° C): [1300...1500]ohms
- Resistor(40° C): [1100...1200]ohms
- Resistor(45° C): [920...1100]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

- B2/5b1 (Intake air temperature sensor)
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 prerequisites

- The power supply of component N10/1 (Driver-side SAM control unit with fuse and relay module) is OK.
- Fault code 9063 is current, and (or) at least one of the relevant actual values is not OK.
Test sequence

- Detach coupling at component B14 (Ambient temperature display temperature sensor).
- Connect resistance simulator to the connector of component B14 (Ambient temperature display temperature sensor).
- Connect resistance substitution unit between sockets (B14)1 and (B14) 2
- Adjust resistance values one after another and compare them with the actual value.
Status of relevant actual value:
- B14 (Ambient temperature display temperature sensor):Warning! Communication with ECU required.
Specified value

- Resistor9.6 kohms:Temperature: [0° C]
- Resistor5.9 kohms:Temperature: [10° C]
- Resistor3.7 kohms:Temperature: [20° C]
- Resistor2.4 kohms:Temperature: [30° C]
- Resistor1.6 kohms:Temperature: [40° C]
Question:Is the actual value o.k.?







YES
The actual value is okay.Possible cause and remedy

- Component B14 (Ambient temperature display temperature sensor) is defective.
End of test







NO
The actual value is not o.k.Possible cause and remedy

- Check lines from B14 (Ambient temperature display temperature sensor) to N10/1 (Driver-side SAM control unit with fuse and relay module) for Short circuit or open circuit.
- Component N10/1 (Driver-side SAM control unit with fuse and relay module) is defective.
End of test







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