Audi Q7: CAN-Bus Terminal Resistance, Checking
General Description
The Engine Control Module -J623- communicates with other
CAN-Bus capable control modules.
The control modules are connected by two data bus wires
which are twisted together (CAN_High and CAN_Low), and exchange
information (messages). Missing information on the CAN-bus is
recognized as a malfunction by the Engine Control Module -J623-
and the other control modules connected to the CAN-bus.
Trouble-free operation of the CAN-Bus requires that it have
a terminal resistance. This central terminal resistance is
located in the Engine Control Module -J623-.
Special tools and workshop equipment
required
- Multimeter.
- Wiring Diagram.
Test requirements
- Fuses OK.
- Battery voltage OK.
- Switch OFF all electrical and electronic accessories.
- Vehicles with automatic transmission, ensure the selector
lever position is in "P".
- Vehicles with manual transmission, ensure the shifter lever
position is in "N" with the parking brake applied.
- Coolant temperature: ≥ 80º C.
- Observe all safety precautions:
→ Chapter "Safety Precautions".
- View clean working conditions:
→ Chapter "Clean Working Conditions".
- For Hybrid vehicles, refer to:
→ Chapter "High Voltage System General Warnings".
Test Procedure
CAN-Bus Terminal Resistance, Powertrain, Checking
General Description
The Engine Control Module -J623- communicates with all
databus capable control modules via a CAN databus.
These databus capable control modules are connected via two
data bus wires which are twisted together (CAN_High and
CAN_Low), and exchange information (messages). Missing
information on the databus is recognized as a malfunction and
stored.
Trouble-free operation of the CAN-bus requires that it have
a terminal resistance. The central terminal resistor is located
in the Engine Control Module -J623-.
Special tools and workshop equipment
required
- Multimeter
- Wiring Diagram
Test requirements
- Fuses OK.
- Battery voltage OK.
- Switch OFF all electrical and electronic accessories.
- Vehicles with automatic transmission, ensure the selector
lever position is in "P".
- Vehicles with manual transmission, ensure the shifter lever
position is in "N" with the parking brake applied.
- Coolant temperature: ≥ 80º C.
- Observe all safety precautions:
→ Chapter "Safety Precautions".
- View clean working conditions:
→ Chapter "Clean Working Conditions".
- For Hybrid vehicles, refer to:
→ Chapter "High Voltage System General Warnings".
Test Procedure
Charge Air Pressure Sensor - G31- / Intake Manifold Temperature Sensor
- G72-, Checking
General Description
The Intake Manifold Temperature Sensor 2 -G430- / Charge Air
Pressure Sensor 2 -G447- is located in the inlet to the intake
manifold. The Engine Control Module -J623- uses the sensor's
signal to regulate the charge air pressure. There is no
substitute function in the event of signal failure. In case of
signal failure, charge air pressure regulation is shut off,
which will lead to a significant reduction in engine output.
Special tools and workshop equipment
required
- Multimeter.
- Wiring Diagram.
- Scan Tool.
Test requirements
- Fuses OK.
- Battery voltage OK.
- Switch OFF all electrical and electronic accessories.
- Vehicles with automatic transmission, ensure the selector
lever position is in "P".
- Vehicles with manual transmission, ensure the shifter lever
position is in "N" with the parking brake applied.
- Coolant temperature: ≥ 80º C.
- Observe all safety precautions:
→ Chapter "Safety Precautions".
- View clean working conditions:
→ Chapter "Clean Working Conditions".
- For Hybrid vehicles, refer to:
→ Chapter "High Voltage System General Warnings".
Test Procedure
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The supercharger Compressor Magnetic Clutch -N421- is
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The following procedure is used to diagnose the Engine
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that is provided to the engine components.
Special tools a
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The camshaft's task is to operate the valves at the right
time and in the right order to control the charge cycle.
Camshaft adjustment using the Exhaust Camshaft Adjustment Valve
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General information
As the driver, you are responsible for making sure
every passenger is sitting correctly in their seat
and maintaining this seating position while driving.
Make sure that:
Every passenger in the vehicle has adjusted his
or her seat correctly
The steering wheel is adjusted cor
Winter tires significantly improve the vehicle's
handling when driving in winter conditions. Because
of their construction (width, compound,
tread pattern), summer tires provide less traction
on ice and snow.
Use winter tires on all four wheels.
Only use winter tires that are approved for your
v