Diesel Exhaust Fluid and Tank, EPA10 and Newer Engines

rv dm 06.04.007

Diesel Exhaust Fluid

Diesel exhaust fluid (DEF) is used in the ATS to lower NOx in the exhaust stream. DEF is colorless and close to odorless (it may have a slightly pungent odor similar to ammonia). It is nontoxic, nonflammable, and biodegradable. It is mildly corrosive to aluminum, but does not affect the strength or structure of the aluminum.

White crystals may be noticeable around components that come into contact with DEF. The crystals are easily removed with water.

DEF consumption varies depending on ambient conditions and vehicle application.

Freezing Conditions

DEF freezes to slush at around 12°F (-11°C). It is not damaged or destroyed if frozen, and is fully usable when thawed. The DEF in the tank is allowed to freeze while a vehicle is non-operational. At start-up, normal operation of the vehicle is not inhibited if the DEF is frozen; an immersion heater with engine coolant flowing through it warms the DEF once the engine is running, allowing the SCR system to operate.

Pre-2013 DEF supply lines are electrically-heated and are purged when the engine is shut down; complete purging of the DEF lines requires approximately five minutes after the engine is shut down.

DEF supply lines with engine model year 2013 and newer are designed to survive freezing conditions while containing DEF, so purging is not required.

DEF Tank

Engines that are compliant with EPA10 and newer regulations are equipped with a DEF tank located forward of the ATS. See Fig.. The DEF tank has a 19 mm filler neck inlet that prevents the hose from a diesel outlet from being inserted, and has a blue cap for easy identification.

ATS

DEF Tank

DEF Gauge (optional)

Fig. 1, DEF Tank With Optional DEF Gauge

The DEF tank will require filling a minimum of approximately every second diesel refuel depending on the DEF tank capacity. 10-, 13-, and 15-gallon tank capacities are available. DEF consumption is approximately 2% of fuel consumption, dependent on vehicle operation. For every 50 gallons of diesel fuel consumed, approximately 1 gallon of DEF will be consumed.

Some vehicles are equipped with a remote DEF fill-port. If so equipped, the remote port is directly opposite the DEF tank on the other side of the vehicle, and has a blue cap over the fill-port. See Fig..

Fig. 2, Remote DEF Fill-Port

Ametek DEF Warnings and Engine Limits

The DEF lightbar indicates the level in the DEF tank as follows.

Four bars illuminated green—Between 75% and 100% full
Three bars illuminated green—Between 50% and 75% full
Two bars illuminated green—Between 25% and 50% full
One bar illuminated green—Between approximately 10% and 25% full
One bar illuminated amber—DEF low, refill DEF
One bar flashing red—DEF empty, refill DEF

Important: Ignoring the DEF warning lights and not refilling the DEF tank will result in limited engine power with a speed limit of 5 mph (8 km/h) eventually being applied. See the engine manufacturer's operation and maintenance manual for further information.

DEF Level Low—Initial and Critical Warnings

When the DEF level reads low the following warnings strongly encourage the driver to refill the DEF tank. See Fig..

The CHECK engine lamp flashes for 30 seconds when the vehicle is started.
The DEF warning lamp illuminates.
One bar of the DEF-level lightbar illuminates solid amber.

Engine performance is limited, with progressively harsher engine power limits applied.

The DEF tank must be filled to cancel the warning sequence.

DEF Warning Lamp (illuminates constantly)

DEF-Level Lightbar (1 bar solid amber)

Fig. 3, DEF Level Low Initial and Critical Warnings

DEF Empty

When the DEF level reads empty, the following warnings are activated. See Fig..

The DEF warning lamp flashes.
The CHECK engine lamp illuminates.
One bar of the DEF-level lightbar flashes red.
A brief audible alert notifies the driver.

Engine performance is limited, with progressively harsher engine power limits applied.

The DEF tank must be filled to cancel the warning sequence.

Note: Engine performance is limited.

DEF Warning Lamp (flashing)

DEF-Level Lightbar (1 bar flashing red)

Fig. 4, DEF Empty Warning

DEF Level Empty and Ignored

If the empty warning is ignored and the DEF is not refilled, the DEF warning lamp flashes, one bar of the DEF-level lightbar flashes red, and the red STOP engine lamp illuminates in addition to the CHECK engine warning lamp. A brief audible alert notifies the driver. See Fig..

Note: The STOP engine, CHECK engine, and DEF lamps illuminate, engine power is limited, speed limit of 5 mph (8 km/h).

DEF Warning Lamp (flashing)

DEF-Level Lightbar (1 bar flashing red)

Fig. 5, DEF Empty and Ignored Warning

If the DEF tank is not refilled, a 5 mph (8 km/h) speed limit will be applied after the next engine shutdown, or while parked and idling.

DEF Quality or SCR Tampering

Notice: Once contaminated DEF has been detected in the SCR system, the vehicle must be taken to an authorized service center to check the SCR system for damage, and to deactivate the warning light and engine limits.

If contaminated DEF or tampering is detected, the DEF warning light flashes, and engine performance is limited with progressively harsher engine power limits applied. If the fault is not corrected, the CHECK engine lamp illuminates, then the STOP engine lamp illuminates and a 5 mph (8 km/h) speed limit will be applied after the next engine shutdown, or while parked and idling. See Fig..

OptiView™ DEF Warnings and Engine Limits

Note: The OptiView instrument panel has a DEF gauge that contains a low DEF warning lamp, which activates when the DEF tank needs to be refilled. Along with the DEF warning lamp activation, warning statements appear in the center of the OptiView panel.

DEF Level—Initial Warning

When the DEF level becomes low, the following warning strongly encourages the driver to refill the DEF tank.

The CHECK engine lamp flashes for 30 seconds when the vehicle is started.
The DEF warning lamp illuminates.

The DEF tank must be filled to cancel the warning sequence.