Audi Q7: Preliminary Check
Note
- Before performing any pin point test or component diagnosis,
a Preliminary Check must be performed.
- Check for Technical Bulletins that may supersede any
information included in the repair manual or GST Manual.
- For Electrical Testing.
- For Fuel System Mechanical Testing.
- For Oxygen Sensor Preliminary Tests.
Electrical Testing
Fuel System Mechanical Testing
Check the following items for possible mechanical delivery
deficiency:
- Fuel level in tank is too low.
- Fuel lines pinched.
- Fuel filter plugged.
- Fuel pump delivery unit internal leak.
- Clogged injectors.
- Poor fuel quantity delivery. Refer to appropriate repair
manual.
Oxygen Sensor Preliminary Tests
Check for the following conditions which can cause Oxygen
Sensor Faults to set without requiring Oxygen Sensor
replacement:
Common issues for lean faults:
- Vacuum leaks - check for failed or loose vacuum lines,
leaking intake gaskets, or any other source of un-metered air
leaks (leaks after the Mass Air Flow Sensor).
- Restricted fuel filter or bent/pinched fuel system lines.
- Incorrect input from other sensors, such as the Mass Air
Flow Sensor, which may not always set a fault.
- Engine misfire.
- Exhaust leaks.
- Camshaft timing.
- Common issues for rich faults:
- Leaking or faulty fuel injector.
- Fuel injector driver shorted in ECM, or wiring short for
injectors (short to ground).
- Leaking or faulty fuel pressure regulator or restricted
return line.
- Faulty fuel pump or fuel pump driver module.
- Incorrect input from other sensors, such as the Mass Air
Flow Sensor, which may not always set a fault.
- Aftermarket components or performance chips.
- Camshaft timing.
Readiness Code
Caution
When performing the Readiness drive cycle operation,
pay strict attention to driving conditions and observe
and obey all posted speed limits.
Readiness code description
Diagnostics are performed at regular intervals during normal
vehicle operation. After repairing an emissions related system,
a readiness code is generated by road testing the vehicle.
If a malfunction is recognized during the drive cycle, it
will be stored in the DTC memory.
The OBD drive cycle operation will be monitored with a hand
held diagnostic tool. Consult the manufacturer's instruction
manual for correct tool operation.
The readiness code is erased every time the DTC memory is
erased or any time the battery is disconnected. If the DTC
memory has been erased or the battery is disconnected, a new
readiness code must be generated.
Only erase the DTC memory if a DTC has been stored.
General recommendations
Most monitors will complete easier and quicker using a
"steady-foot" and "smooth" acceleration during the drive cycle
operation.
Operating conditions
For the EVAP monitor test, the coolant temperature and the
ambient air temperature must be between 10º C and 35º C with a
difference between them no greater than 4º C. The ambient air
temperature must not change more than 4º C during the drive
cycle procedure (e.g. when driving out of a heated workshop in
the winter).
Note
Do not assume that the scan tool ID and engine code are
correct if the scan tool communicates. The scan tool does not
use the ID to establish communication-the units are
automatically identified.
Test requirements
- NO DTC in memory.
- Switch OFF all electrical and electronic accessories.
- Necessary driving speed: 50 - 70 mph.
- Drive profile takes approximately 60 - 90 min.
Readiness Drive Cycle Procedure
- CONNECT: Scan Tool.
- If any engine monitor fails the drive cycle test. Repeat the
drive cycle test until all engine monitors have successfully run
through and passed.
Note
- When repeating the drive cycle operation for a failed
evaporative or thermostat monitor, allow the engine to cool
until the coolant temperature and the ambient air temperature
are between 10º C and 35º C with a difference between them no
greater than 4º C and then repeat the drive cycle operation.
- Depending on the scan tool used, the readiness code status
may be displayed as complete, passed or OK. At an ambient air
temperature < 7º C, the setting of the readiness for the NOx
catalytic converter test is delayed. Here the vehicle must be
driven considerably longer.
Readiness Codes and Monitoring Completed
1 - If any engine monitor fails the drive cycle test, repeat the
drive cycle test until all engine monitors have successfully run
through and passed.
2 - If the drive cycle operation fails again:
3 - Check the DTC memory for stored DTCs.
4 - Repair the vehicle if necessary.
5 - Repeat the drive cycle operation until all engine monitors
have successfully run through and passed.
6 - Remove the scan tool and switch the ignition off.
READ NEXT:
Diagnostic Mode 01 makes it possible to access current
emissions-related measured values and diagnostic data. The
original measured values (no replacement values), input and
output data and system
Diagnostic Mode 06 makes it possible to retrieve test
results for special components and systems which are
continuously or not continuously monitored. If the diagnosis of
a system is complete, the
Mode 07 makes it possible to check emissions-related faults
which appeared during the current or last driving cycle (pending
DTCs).
A pending DTC is saved the first time a fault is detected
(output
SEE MORE:
Overview - Sun Shade, Side Window
1 - Bolt
3.3 Nm
Quantity: 4
2 - Sun Shade Cover
Removing and installing. Refer to
→ Chapter "Sun Shade, Removing and Installing, Side Window".
3 - Bolt
1.7 Nm
Quantity: 2
4 - Sun Shade Mounting Eye
Remov
General Information
Indicators on pressure gauge
1 - Temperature scale for refrigerant R134a CF3-CH2F or
CH2F-CF3.
2 - Pressure scale
Note
Pressure is measured in different units: 1 MPa (145 psi)
corresponds to 10 bar (145 psi) positive pressure. 1 bar (14.5
psi) abso