ME9.7

SBC : Undervoltage supply


Possible cause:

- N3/10 (ME-SFI [ME] control unit)
Affected functions:

- Battery / On-board electrical system

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Test 1: Check power supply of component N3/10 (ME-SFI [ME] control unit).

Test 2: Check component A7/3n1 (SBC control unit).

1. Check power supply of component N3/10 (ME-SFI [ME] control unit).

Test 1.1: Test voltage supply of circuit 87. ( Check using actual value )

Test 1.2: Test voltage supply of circuit 30.

Test 1.3: Test current consumption of component N10/1kR (Circuit 87 relay, engine).

Test 1.4: Test voltage supply of circuit 15.

1.1. Test voltage supply of circuit 87. ( Check using actual value )
Test prerequisite

- The voltage test at component G1 (Battery) is o.k.
- Ignition ON
Status of relevant actual value:
- Battery voltage:Warning! Communication with ECU required.
Specified value

- Battery voltage[11.0 ... 15.0] V
Question:Is the actual value o.k.?

YES
The actual value is okay.End of test

NO
The actual value is not o.k.Possible cause and remedy

- Test voltage supply of circuit 30.
- Test voltage supply of circuit 87.


1.2. Test voltage supply of circuit 30.
Connect socket box to component N3/10 (ME-SFI [ME] control unit).
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 voltage supply of circuit 30.
Test sequence

- Measure direct voltage with multimeter between sockets [ F.2 ] 98 and [ F.16 ] 112 of the 35-pole socket box tester.
- Switch on ignition.
Specified value

- Voltage[11.0...15.0] V
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

- F34f42 (Fuse 42)
- Lines
End of test







1.3. Test current consumption of component N10/1kR (Circuit 87 relay, engine).
Connect socket box to component N3/10 (ME-SFI [ME] control unit).
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 current consumption of component N10/1kR (Circuit 87 relay, engine).
Test sequence

- Measure direct current with multimeter between sockets [F.4] 100 and [F.27] 123 of the 126-pole socket box tester.
- Switch on ignition.
Specified value

- Amperage[0.1...0.3] A
Question

- Is the measurement value OK?


YES
The test was okay.End of test

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

- Lines to component N10/1kR (Circuit 87 relay, engine)
- N10/1kR (Circuit 87 relay, engine)
End of test

1.4. Test voltage supply of circuit 15.
Connect socket box to component N3/10 (ME-SFI [ME] control unit).
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 voltage supply of circuit 15.
Test sequence

- Measure direct voltage with multimeter between sockets [ F.2 ] 98 and [ F.15 ] 111 of the 35-pole socket box tester.
- Switch on ignition.
Specified value

- Voltage[11.0...15.0] V
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

- N10/1f52 (Fuse 52)
- Lines
End of test







2. Check component A7/3n1 (SBC control unit).
Read and process fault code from control module A7/3n1 (SBC control unit).
Possible cause and remedy

- Read and process fault code from control module A7/3n1 (SBC control unit).
End of test