Manufacturer Code Charts: 2234
Intake air temperature sensor 1 has a malfunction.
Possible cause:
- B2/6 (Left hot film mass air flow sensor)
- B2/7 (Right hot film mass air flow sensor)
- B11/4 (Coolant temperature sensor)
Affected functions:
- Engine cooling
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Test 1: Check component B2/6 (Left hot film mass air flow sensor).
Test 2: Check component B2/7 (Right hot film mass air flow sensor).
Test 3: Check component B11/4 (Coolant temperature sensor).
1. Check component B2/6 (Left hot film mass air flow sensor).
Test 1.1: Check signal of component via actual value with engine OFF.
Test 1.2: Check signal of component via actual value with engine speed greater than 3000 rpm.
Test 1.3: Check power supply of component.
1.1. Check signal of component via actual value with engine OFF.
Warning!Communication with ECU required.
1.2. Check signal of component via actual value with engine speed greater than 3000 rpm.
Warning!Communication with ECU required.
1.3. Check power supply of component.
Test prerequisite
- The actual value is not o.k.
Test sequence
- Switch off ignition.
- Detach coupling at component .
- Measure direct voltage with multimeter between sockets (B2/6) 2 and (B2/6) 1
- Switch on ignition.
Specified value
- Voltage[11.0...15.0] V
Question
- Is the measurement value OK?
YES
The actual value is okay.Further possible causes of fault
- Unmetered air
- Signal wire
- B2/6 (Left hot film mass air flow sensor)
End of test
NO
The measurement value is not OK.Possible cause and remedy
- K40/4f43 (Fuse 43)
- Cable for voltage supply
End of test
2. Check component B2/7 (Right hot film mass air flow sensor).
Test 2.1: Check signal of component via actual value with engine OFF.
Test 2.2: Check signal of component via actual value with engine speed greater than 3000 rpm.
Test 2.3: Check power supply of component.
2.1. Check signal of component via actual value with engine OFF.
Warning!Communication with ECU required.
2.2. Check signal of component via actual value with engine speed greater than 3000 rpm.
Warning!Communication with ECU required.
2.3. Check power supply of component.
Test prerequisite
- The actual value is not o.k.
Test sequence
- Switch off ignition.
- Detach coupling at component .
- Measure direct voltage with multimeter between sockets (B2/7) 2 and (B2/7) 1
- Switch on ignition.
Specified value
- Voltage[11.0...15.0] V
Question
- Is the measurement value OK?
YES
The actual value is okay.Further possible causes of fault
- Unmetered air
- Signal wire
- B2/7 (Right hot film mass air flow sensor)
End of test
NO
The measurement value is not OK.Possible cause and remedy
- K40/4f43 (Fuse 43)
- Cable for voltage supply
End of test
3. Check component B11/4 (Coolant temperature sensor).
Test 3.1: Check component B11/4 (Coolant temperature sensor) using actual value.
Test 3.2: Check signal lines on component B11/4 (Coolant temperature sensor).
Test 3.3: Check internal resistance of component B11/4 (Coolant temperature sensor).
3.1. 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°C]: [3.45...3.32] V
- Voltage[30°C]: ..[2.93...2.82] V
- Voltage[40°C]: [2.41...2.32] V
- Voltage[50°C]: [1.93...1.86] V
- Voltage[60°C]: [1.51...1.46] V
- Voltage[70°C]: [1.18...1.13] V
- Voltage[80°C]: [0.90...0.87] V
- Voltage[90°C]: [0.70...0.67] V
- Voltage[100°C]: [0.54...0.25] V
- Voltage[110°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
3.2. 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
3.3. Check internal resistance of component B11/4 (Coolant temperature sensor).
Test prerequisite
- The actual value is not o.k.
Test sequence
- Switch off ignition.
- Disconnect connector at component B11/4 (Coolant temperature sensor).
- Measure resistance with multimeter between pins ( B11/4 ) 1 and ( B11/4 ) 2
Specified values
- Resistor(20° C): [3030...3130]ohms
- Resistor(30° C]: [1950...2050]ohms
- Resistor(40° C): [1275...1375]ohms
- Resistor(50° C): [850...950]ohms
- Resistor(60° C): [600...650]ohms
- Resistor(70° C): [420...460]ohms
- Resistor(80° C): [305...335]ohms
- Resistor(90° C): [220...240]ohms
- Resistor(100° C): [160...180]ohms
- Resistor(110° C): [120...140]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
- B11/4 (Coolant temperature sensor)
End of test