111A00

Component NOx sensor upstream of SCR catalytic converter has a plausibility error.


Possible cause:

- NOx sensor upstream of SCR catalytic converter
Affected functions:

- Power generation

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Test 1: Check component NOx sensor upstream of SCR catalytic converter.

1. Check component NOx sensor upstream of SCR catalytic converter.

Test 1.1: Inspect CAN link between component NOx sensor upstream of SCR catalytic converter and component N3/9 (CDI control unit).

Test 1.2: Check power supply of component NOx sensor upstream of SCR catalytic converter.

1.1. Inspect CAN link between component NOx sensor upstream of SCR catalytic converter and component N3/9 (CDI control unit).
If several fault codes regarding CAN communication have occurred, the following causes of the fault are likely

- Short circuit or open circuit of CAN wires
- Voltage supply of component NOx sensor upstream of SCR catalytic converter
Figure legend

- N37/7 (NOx control unit downstream of diesel particulate filter)
- N37/7b1(NOx sensor upstream of SCR catalytic converter)
Test sequence

- Switch off ignition.
- Detach coupling at component N37/7 (NOx control unit downstream of diesel particulate filter).
- Detach coupling at component N37/8 (NOx control unit downstream of SCR catalytic converter).
- Measure resistance with multimeter between sockets (N37/7x1) 3 and (N37/7x1) 4
Specified value

- Resistor[55...65]ohms
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

- Check lines and connectors between components N37/7 (NOx control unit downstream of diesel particulate filter) and N3/9 (CDI control unit) for short and open circuit.
End of test

1.2. Check power supply of component NOx sensor upstream of SCR catalytic converter.
Figure legend

- N37/7 (NOx control unit downstream of diesel particulate filter)
- N37/7b1(NOx sensor upstream of SCR catalytic converter)
Test prerequisite

- Battery voltage is OK.
- The fuses are OK.
Test sequence

- Switch off ignition.
- Disconnect connector at component N37/7 (NOx control unit downstream of diesel particulate filter).
- Measure direct voltage with multimeter between sockets (N37/7x1) 2 and (N37/7x1) 1
- 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

- F58f104 (Fuse 104)
- Line from component N37/7 (NOx control unit downstream of diesel particulate filter) to component F58 (Engine compartment fuse and relay box)
End of test