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On Board Diagnostic
System (OBD)
The On-Board Diagnostic System monitors the
engine and transmission components that influ
ence emissions.
F ig . 176 Footwell o n le ft s ide of th e vehicle: con nectio n
port fo r th e On -Board Diagnostic System (OBD)
On -Board Diagnostic S ystem
Eng ine data can be read out at the On-Board Di
agnostic System connection port using a special
testing device
r::;, fig . 176.
Ind icat or light
If thE' ¢..ift indicator light blinks or turns on, there
is a malfunction that is causing poor emissions
quality and that could damage the catalytic con
verter .
Drive s lowly to an authorized Audi dealer or au
thor ized Audi Service Facility to have the mal
function corrected .
The indicator light can also turn on if the fuel fill
er cap is not closed correct ly
c::;, page 186.
A WARNING
Incorrect use of the connection port for the
On-Board Diagnostic System can cause mal
functions, which can then result in acc idents
and ser io us injuries .
- Only allow an author ized Audi dealer or au
thorized Aud i Serv ice Facility to read out the
engine data.
-
Chec king and Filling
Engine compartment
Working in the engine compartment
Special care is required if you are working in the
engine compartment
For wo rk in the engine com part ment , such a s
che cking and filling fluids, there i s a ris k of i n
jur y, sc alding, a cci dent s, and b urn s. For t his
r easo n, foll ow all the w arnings and g en e ral
s afe ty pre ca ution s pro vided in the f ollowing
in
formati on. Th e engine compartm ent i s a dan
ge rou s area in the vehicle .
r::;, &..
A WARNING
-Turn the engine off.
- Sw itch the ignition off.
- Set the parking brake.
- Select the "P" selector lever position .
- Let the eng ine cool down .
- Never open the hood when there is steam or
coolant escaping from the engine compart ment, because there is a risk that you could
be burned . Wait unt il no steam or coolant is
escaping.
- Keep children away from the eng ine com
partment .
- Never sp ill fluids on a hot engine. These flu
ids (such as the freeze protection contained in the coolant) can catch fire.
- Avoid short c ircuits in the electrical system .
- When working in the engine compartment,
remember that the radiator fan can switch
on even if the ignition is switched off, which increases the ris k of personal injury .
- Never open the cap on the coolant expan
sion tank when the engine is warm . The
coo ling system is under pressure.
-To protect your face, hands, and arms from hot steam or coolant, cover the cap with a
large cloth when opening .
- Do not remove the eng ine cover under any
circumstances . This increases the risk of
bu rns .
- If tests need to be performed with the en
g ine runn ing, there is add it iona l danger due
to mov ing components (such as the ribbed
~
1 8 9
Checking and Filling
Coolant Freeze protec-
additi ve tion
Warm min. 40% min. -13 °F
regions max. 45% (-25 °C)
Cold min. 50% max. -40
°F
regions max. 55% (-40 °C)
([) Note
- Before the start of winter, have an author
ized Audi dealer or authorized Audi Service
Facility check if the coolant additive in your
vehicle matches the percentage appropriate
for the climate. This is especially important
when driving in colder climates.
- If the appropriate coolant additive is not
available in an emergency, do not add any
other additive. You could damage the en
gine. If this happens, only use water and re store the correct mixture ratio with the
spec ified coolant additive as soon as possi
ble.
- Only refill with new coo lant.
- Radiator sealant must not be mixed w ith
the coo lant .
Adding coolant
F ig. 181 Engine compartment: coolant expans ion tank
cover
Observe the safety precautions~ page 189,
Working in the engine compartment .
Checking the engine coolant level
• Park the vehicle on a leve l surface .
• Switch the ignition off.
• Read the coolan t leve l on the coo la nt expansion
tank~ page 192, fig . 179. The coolant level
must be between the MIN and MAX markings
196
when the engine in cold. When the engine is
warm it can be slightly above the MAX marking .
Adding coolant Requirement: there must be a residual amount of
coolan t in the expansion tan k
~CD -
• Let the engine cool down .
• Place a cloth over the coolant expansion tank
cap and unscrew the cap counterclockw ise
~ & -
... Add coo lant m ixed in the cor rect ratio
~ page 195 up to the MAX marking.
• Make sure that the fluid level remains stab le .
Add more coolant if necessary .
• Close the cap securely.
Coolant loss usually ind icates there is a leak . Im
mediate ly drive your vehicle to an authorized
Audi dealer or authorized Audi Service Fac ility
and have the cooling system inspected. If the
cooling system is not leaking, a loss can come
from the coolant boiling through overheat ing
and being pushed out of the cooling system .
A WARNING
- The cooling system is under pressure. Do
not open the coo lant expansion ta nk cap
when the engine is hot. This increases the
risk o f bur ns.
- The coolan t addi tive and the coolant can be
dangerous to your health. For t his reason,
keep the coolant in the original container
and away from children. There is a risk of
poisoning.
- When working in the engine compartment,
remember that the radiator fan can switch
on even if the ignition is switched off, which
increases the risk of injury.
(D Note
Do not add coolant if the expansion tank is
empty. A ir cou ld enter the cooling system and
damage the engine. If this is the case, do not
continue driving. See an authorized Audi deal
er or authorized Audi Serv ice Facility for assis
tance.