Manufacturer Code Charts: 2065
Component B11/4 (Coolant temperature sensor) has a short circuit to ground.
Possible cause:
- B11/4 (Coolant temperature sensor)
- Y110 (Three-disk thermostat valve)
- The cooling performance of the engine cooling system is poor.
Affected functions:
- Engine diagnosis
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Test 1: The cooling performance of the engine cooling system is poor.
Test 2: Check component B11/4 (Coolant temperature sensor).
Test 3: Check component Y110 (Three-disk thermostat valve).
1. The cooling performance of the engine cooling system is poor.
The cooling performance of the engine cooling system is poor.
2. Check component B11/4 (Coolant temperature sensor).
Test 2.1: Check component B11/4 (Coolant temperature sensor) using actual value.
Test 2.2: Check signal lines on component B11/4 (Coolant temperature sensor).
Test 2.3: Check internal resistance of component B11/4 (Coolant temperature sensor).
2.1. 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
2.2. 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
2.3. 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
3. Check component Y110 (Three-disk thermostat valve).
Test 3.1: Component Y110 (Three-disk thermostat valve) is mechanically damaged or it sticks.
Test 3.2: Test current consumption of component Y110 (Three-disk thermostat valve).
3.1. Component Y110 (Three-disk thermostat valve) is mechanically damaged or it sticks.
Test 3.1.1: Y110 (Three-disk thermostat valve) : Coolant temperature is not reached.
Test 3.1.2: Y110 (Three-disk thermostat valve) : Coolant temperature is too high.
3.1.1. Y110 (Three-disk thermostat valve) : Coolant temperature is not reached.
Warning!Communication with ECU required.
3.1.2. Y110 (Three-disk thermostat valve) : Coolant temperature is too high.
Warning!Communication with ECU required.
3.2. Test current consumption of component Y110 (Three-disk thermostat valve).
Figure legend
- A -ConnectionTest cable 35-pin socket box
- 001 -Sockets of component N3/10 (ME-SFI [ME] control unit)
- 05 -35-pin socket box
- 050 -126-pin socket box
- 108 -Test cable 266 589 01 63 00
- N3/10 (ME-SFI [ME] control unit)
- II 1-63ConnectionTest cable
- III 64-126ConnectionTest cable
Warning!
- Connection A of test cable 108 may NOT be connected to connection B of the 126-pin socket box (050).
Continue to test with button F2
Test sequence
- Measure direct current with multimeter between sockets [F.4] 100 and [M.54] 54 of the 126-pole socket box tester.
- Switch on ignition.
Specified value
- Amperage[0.6...1.2] A
Question
- Is the measurement value OK?
YES
The measurement value is OK.End of test
NO
The measurement value is not OK.Possible cause and remedy
- N10/1f57 (Fuse 57)
- N10/1kR (Circuit 87 relay, engine)
- Check lines from component N3/10 (ME-SFI [ME] control unit) to component Y110 (Three-disk thermostat valve).
- Y110 (Three-disk thermostat valve)
End of test