[1] Check component B11/4 (Coolant temperature sensor).: Open circuit in wiring / Short circuit to positive

[1] Check component B11/4 (Coolant temperature sensor).: Open circuit in wiring / Short circuit to positive

Test 1: Check component B11/4 (Coolant temperature sensor).

1. Check component B11/4 (Coolant temperature sensor).
Check actual value B11/4 (Coolant temperature sensor).
Note

- The fault code is stored even if the lines to component B11/4 (Coolant temperature sensor) are interrupted.
- If fault exists, vehicle continues operating with substitute value from the temperature model.
Test prerequisite

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

- If the connection is unplugged at component B11/4 (Coolant temperature sensor), the value is approx. -40° C.
- Bridge pin 1 in pin 2 at the unplugged connection of component B11/4 (Coolant temperature sensor).The value is approx. 137° C.
Question

- Is the actual value o.k.?


YES
The actual value is okay.Further procedure

- Test wiring and plug connections between control module N3/9 (CDI control unit) and B11/4 (Coolant temperature sensor) for Loose contact, repair or replace if necessary.
End of test

NO
Voltage supply of component B11/4 (Coolant temperature sensor)
Figure legend

- B11/4 (Coolant temperature sensor)
Special tool

- Adapter cable220 589 00 99 34
Test prerequisite

- Switch off ignition.
- Detach coupling at component B11/4 (Coolant temperature sensor).
- Connect adapter cable no. 220 589 00 99 34 to engine wiring harness B11/4 (Coolant temperature sensor).
- Measure direct voltage with multimeter between sockets (B11/4x1) 1 and (B11/4x1) 2
- Switch on ignition.
Specified value

- Voltage[4.6...5.1] V
Question

- Is the measurement value OK?







YES
Check internal resistance of component B11/4 (Coolant temperature sensor).
Figure legend

- B11/4 (Coolant temperature sensor)
Note

- If fault exists, vehicle continues operating with substitute value from the temperature model.
Test prerequisite

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

- Switch off ignition.
- Connect adapter cable no. 220 589 00 99 34 at component B11/4 (Coolant temperature sensor).
- Test resistance.
- Measure resistance with multimeter between sockets (B11/4) 1 and (B11/4) 2
Specified value

- Resistor[20° C]: [2945...3240]ohms
- Resistor[60° C]: [609...653]ohms
- Resistor[90° C]: [229...242]ohms
- Resistor[120° C]: [99...103]ohms
Question

- Is the measurement value OK?







YES
The measurement value is OK.Further procedure

- Test signal line between components N3/9 (CDI control unit) and B11/4 (Coolant temperature sensor) for Open circuit.
End of test

NO
The measurement value is not OK.Possible cause and remedy

- Replace component B11/4 (Coolant temperature sensor).
End of test

NO
The measurement value is not OK.Further procedure

- Test signal line between components N3/9 (CDI control unit) and B11/4 (Coolant temperature sensor) for Open circuit.
End of test