Land Rover Discovery: Diesel Exhaust Fluid ( DEF ) Quality. 16 MY NAS B - 17 MY NAS
B
![Diesel Exhaust Fluid ( DEF ) Quality. 16 MY NAS B - 17 MY NAS B](images/books/227/index441(18).jpg)
![Diesel Exhaust Fluid ( DEF ) Quality. 16 MY NAS B - 17 MY NAS B](images/books/227/index442(18).jpg)
Diesel Exhaust Fluid (DEF) Quality
Prior to the NOx sensor and the monitoring function becoming operational,
the sensor must have reached its 'dew point'. This is the point where the
moisture content in the exhaust gas has evaporated and can no longer
damage the NOx sensor. In normal ambient conditions, this process
typically takes around 6 to 10 minutes. If a malfunction is detected during
the operation of the NOx sensor, a reversible fault is stored. If a malfunction
is detected over two (NAS variants) or three (EU6 variants) consecutive drive
cycles, a permanent fault is stored and the MIL is activated
The following monitoring is performed on the NOx sensors
- Signal plausibility and correction factor limits
- Circuit continuity between the sensor control unit and probe element
- Operating temperature reached after a defined heating period
Private CAN Bus - Monitoring
The following components are connected to the ECM via a private CAN
bus. The ECM provides a gateway, for communication to the vehicle CAN
bus
- Heater control unit
- NOx sensor control unit(s)
The following CAN communication monitoring applies to these components
- Signal time-out
- Signal check sum
The DEF injector, DEF pump, temperature and level sensors are hardwired
to the ECM and do not involve CAN communication
DIESEL EXHAUST FLUID ( DEF ) SUPPLY AND METERING SYSTEM MALFUNCTIONS . 16
MY NAS B - 17 MY NAS B
![DIESEL EXHAUST FLUID ( DEF ) SUPPLY AND METERING SYSTEM MALFUNCTIONS . 16 MY NAS B - 17 MY NAS B](images/books/227/index443(18).jpg)
The OBD system monitors components and the functionality of the DEF
supply and metering system. If a malfunction is detected a message centre
warning is displayed. If no action is taken to rectify the warning malfunction,
this will eventually lead to a 'No engine restart' situation
![DIESEL EXHAUST FLUID ( DEF ) SUPPLY AND METERING SYSTEM MALFUNCTIONS . 16 MY NAS B - 17 MY NAS B](images/books/227/index444(18).jpg)
![DIESEL EXHAUST FLUID ( DEF ) SUPPLY AND METERING SYSTEM MALFUNCTIONS . 16 MY NAS B - 17 MY NAS B](images/books/227/index445(19).jpg)
![DIESEL EXHAUST FLUID ( DEF ) SUPPLY AND METERING SYSTEM MALFUNCTIONS . 16 MY NAS B - 17 MY NAS B](images/books/227/index446(17).jpg)
![DIESEL EXHAUST FLUID ( DEF ) SUPPLY AND METERING SYSTEM MALFUNCTIONS . 16 MY NAS B - 17 MY NAS B](images/books/227/index447(18).jpg)
Diesel Exhaust Fluid (DEF) Supply and Metering System Malfunctions
The following DEF supply and metering system malfunctions may trigger
the message centre warning system
- Pressure build up in the supply line
- Metering/injection time to closed loop
- Over pressure in supply line
- Under pressure in supply line
- Injection valve open circuit
- SCR system relay open circuit
- Solenoid pump(s) open circuit
- Combined temperature/level sensor open circuit
- Missing communication with upstream NOx sensor (NAS variants only)
- Missing communication with downstream NOx sensor
QANDA
![QANDA](images/books/227/index448(17).jpg)
![QANDA](images/books/227/index449(17).jpg)
READ NEXT:
DTC INDEX
For a complete list of all diagnostic trouble codes that could be logged on
this vehicle, please refer to Section 100-00. Engine Control
COMPONENT LOCATION
Diesel Exhaust Fluid (DEF) filler assembly
Engine Control Module (ECM)
Diesel Exhaust Fluid (DEF) tank
Diesel Exhaust Fluid (DEF) tank module
Diesel Exhaust Fluid (DEF) heat
SEE MORE:
Installation
NOTE:
Make sure that a zinc rich primer is applied to any bare metal
surfaces.
Dress the flanges where necessary
Clean and prepare the panel surfaces.
CAUTION:
This step requires the aid of another technician as the side
panel is heavy.
Offer up the new side panel and clamp into p
This program encourages a more efficient
driving style and modifies vehicle settings
to improve fuel economy.
Press the button to switch the ECO
program on/off, a message will appear in
the Message centre.
When selected, engine and transmission
settings are automatically changed to
promote an effi