Chevrolet 4500 HD 2023 Manual page 158

Obey all cautions posted in filling
stations.
When DEF is spilled, wash it away with
water and wipe the area clean.
Add API certified DEF only (or ISO: AUS
32). Do not fill the DEF tank with any
substance other than the DEF.
Any substance other than the DEF may
cause a breakdown to the SCR system.
Use the DEF handling equipment made of
correct materials (Polyethylene or
Stainless-steel).
Avoid contamination from using dirty
funnel for filling.
If a fluid other than the specified DEF is
mistakenly added, incorrect fluid may
cause a failure. Have it inspected and
serviced at a dealer immediately.
Ammonia odor may be generated when
the DEF is exposed to high temperature.
The sight gauge is for filling only, refer to
the IP gauge for actual DEF level. Do not
add DEF above the F position on the sight
gauge. DEF may leak from the breather
hose while driving. Also, the sensor may
be broken when DEF freezes.
Do not put your feet on or stand on the
DEF tank. The tank, pipe or sensors may
be damaged.
After stopping the engine, a flow sound
may be heard from the DEF tank or DEF
supply pump. This sound occurs as the
DEF in the piping is returning to the tank,
and does not indicate an abnormality.
See Winter Driving 0 125.
Adding DEF
1. Turn the engine control switch to the
ACC or LOCK position and make sure to
stop the engine.
2. Wipe off dust or dirt from around the
filler port of the DEF tank.
Driving and Operating
3. Turn and remove the filler cap.
4. Refill the tank up to the F position in the
sight gauge on the front face of the
tank. The sight gauge is for filling only,
refer to the IP gauge for actual DEF level.
The DEF may overflow from the filler
port if it is added in excess of the F
position.
5. Tighten the cap after refilling is
completed.
6. Wipe off DEF that is spilled at refilling.
Warning
On occasion, you may notice an odor
when the DEF tank is opened. Do not
sniff the filler port, etc.
When refilling the DEF tank: Failure to
follow the above instructions could result
in a fire or a breakdown of the selective
catalytic reduction (SCR) system.
Do not dilute DEF with water.
Do not add substances such as gasoline
or diesel fuel to the DEF tank. You and
others could be seriously injured.
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