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Home >> Mercedes Benz Truck >> 2012 >> ML 350 BLUETEC (166.024) V6-3.0L DSL Turbo (642.826) >> Repair and Diagnosis >> A L L Diagnostic Trouble Codes ( DTC ) >> Testing and Inspection >> Manufacturer Code Charts >> 186F00

186F00


Component Y133 (Coolant pump switchover valve) has a malfunction.


Possible cause:

- Y133 (Coolant pump switchover valve)
Affected functions:

- Power generation

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Test 1: Check component Y133 (Coolant pump switchover valve).

1. Check component Y133 (Coolant pump switchover valve).

Test 1.1: Electric test of component Y133 (Coolant pump switchover valve)

Test 1.2: Check vacuum supply of component Y133 (Coolant pump switchover valve).

1.1. Electric test of component Y133 (Coolant pump switchover valve)
Check signal line of component Y133 (Coolant pump switchover valve) for short circuit to ground.
Figure legend

- Y133x1 (Coolant pump switchover valve electrical connector)
Special tool

- Adapter cable220 589 00 99 34
Test sequence

- Switch off ignition.
- Disconnect the socket M at control module N3/9 (CDI control unit).
- Disconnect connector Y133x1 (Coolant pump switchover valve electrical connector).
- Connect adapter cable to engine wiring harness.
- Measure resistance with multimeter between socket (Y133x1) 1 and ground
- Connect adapter cable to component Y133x1 (Coolant pump switchover valve electrical connector).
- Measure resistance with multimeter between pins (Y133x1) 1 and ground.
Specified value:

- Resistorinfiniteohms
Question

- Are the measurement values OK?







YES
Check power supply of component Y133 (Coolant pump switchover valve).
The measurement values are OK.Figure legend

- Y133x1 (Coolant pump switchover valve electrical connector)
Special tool

- Adapter cable220 589 00 99 34
Test sequence

- Switch off ignition.
- Disconnect connector Y133x1 (Coolant pump switchover valve electrical connector).
- Connect adapter cable no. 220 589 00 99 34 to engine wiring harness Y133x1 (Coolant pump switchover valve electrical connector).
- Measure direct voltage with multimeter between pins (Y133x1) 1 and (Y133x1) 2
- Switch on ignition.
Specified value

- Voltage[11...14] V
Question

- Is the measurement value OK?







YES
Check internal resistance of component Y133 (Coolant pump switchover valve).
The measurement value is OK.Figure legend

- Y133x1 (Coolant pump switchover valve electrical connector)
Test sequence

- Switch off ignition.
- Disconnect connector Y133x1 (Coolant pump switchover valve electrical connector).
- Connect adapter cable no. 220 589 00 99 34 at component Y133x1 (Coolant pump switchover valve electrical connector).
- Test resistance.
- Measure resistance with multimeter between sockets (Y133x1) 1 and (Y133x1) 2
Specified value

- Resistor[20...33]ohms
Question

- Is the measurement value OK?







YES
The measurement value is OK.Possible cause and remedy

- Check vacuum supply of component Y133 (Coolant pump switchover valve).


1.1. No further information available.

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

- Check lines and connectors between components Y133x1 (Coolant pump switchover valve electrical connector) and Y133 (Coolant pump switchover valve) for loose contact, damage and corrosion, repair or replace if necessary.
- Inspect component Y133 (Coolant pump switchover valve) for mechanical damage, replace if necessary.
End of test

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

- Check lines and connectors between component Y133x1 (Coolant pump switchover valve electrical connector) and control unit N3/9 (CDI control unit) for short circuit, open circuit, loose seating and damage.
End of test

NO
The measurement values are not OK.Further procedure

- Test cables and connections, rectify any short circuit.
End of test

1.2. Check vacuum supply of component Y133 (Coolant pump switchover valve).
Check vacuum supply.
Figure legend

- 019Vacuum tester201 589 13 21 00
- aVacuum line from component Vacuum pump to component A7/7 (Brake booster)
- bVacuum fitting for auxiliary consumers
Special tool

- Vacuum tester201 589 13 21 00
- Y distributor117 078 01 45
Test sequence

- Connect vacuum tester 201 589 13 21 00 with Y distributor to connection b.
- Engine at idle
Specified value

- Pressure >700 mbar after approx. 30 s
Question

- Is the measurement value OK?







YES
Test function of component Y133 (Coolant pump switchover valve).
Figure legendPicture 1

- Y133 (Coolant pump switchover valve)
- aY distributor117 078 01 45
Figure legendPicture 2

- Y133 (Coolant pump switchover valve)
- 1Air admission
- 2Vacuum supply from vacuum pump
- 3Output
Special tool

- Vacuum tester201 589 13 21 00
- Y distributor117 078 01 45
Test sequence

- Switch off ignition.
- Detach vacuum hose from connection 2 of component Y133 (Coolant pump switchover valve) and seal with stop plug.
- Connect vacuum tester 201 589 13 21 00 with Y-distributor fitting to connection 3 of component Y133 (Coolant pump switchover valve).
- Connect vacuum pump to Y-distributor fitting.
- Switch on ignition.
Continue with button F2













Warning!Communication with ECU required.


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

- Inspect pneumatic lines for leaks.
- Test electrical accessories.
- Check component A7/7 (BAS brake booster).
- Check component Vacuum pump.
End of test

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