P0597

The coolant thermostat has an electrical fault or open circuit.


Possible cause:

- Y110 (Three-disk thermostat valve)
- N10/1kC (Circuit 87 relay, engine)
- N10/1f23 (Fuse 23)
- Voltage supply via component Z7/36 (Circuit 87 M2e connector sleeve)
Affected functions:

- Heating
- Engine cooling

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Test 1: Arrangement of fuses

Test 2: Power supply

Test 3: Check component Y110 (Three-disk thermostat valve).

1. Arrangement of fuses
Figure legend/figure

- N10/1 (Front SAM control unit with fuse and relay module)
Fuses

- FuseF21-F66
Relays

- K =N10/1kK (Wiper park position heater relay)
- J =N10/1kJ (Circuit 15 relay, starter)
- H =N10/1kH (Circuit 50 relay, starter)
- G =N10/1kG (Circuit 15R relay)
- F =N10/1kF (Fanfare horn relay)
- B =N10/1kB (Air suspension compressor relay)
- C =N10/1kC (Circuit 87 relay, engine)
- D =N10/1kD (Circuit 15 relay)
- E =N10/1kE (Circuit 87 relay, chassis)
- A =N10/1kA (Air pump relay)













2. Power supply

2. No further information available.


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.52] 52 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

- N10/1f23 (Fuse 23)
- N10/1kC (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