Overview
AutoElevate (AE) is an optional feature that automatically increases engine RPM and uses engine thermal
controls to help manage/eliminate hydrocarbon (HC) buildup from achieving a level where it could damage
the aftertreatment system.

Enabling AE will help minimize driver action needed during periods of low aftertreatment temperature and
extended idle operation; however, some units may still see some HC absorption faults log and there are
several scenarios which could cause this, some that are completely normal and not indicative of a failure.
HC cleanup also occurs over the road during normal operation when ATS temperatures are high enough for
controlled elimination of the excess fuel.
An AE event is normally15-20 minutes maximum, depending on ambient and ATS temperature conditions.

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Normal Operation
• AE requires vehicles meet certain safety interlocks for activation:
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Transmission in Neutral
Park Brake set to ON
Clutch out (not depressed)
Road speed = 0.0mph/kmh
Engine at idle speed (slow or fast)
PTO governor not enabled
Regen inhibit switch not enabled (not equipped on all units)
If one or more of the above interlocks is not met FOR THE DURATION of the
regen/AE event, either due to component fault or driver input, HC faults will be
more prevalent.
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Driver & Operational Inputs
• Drivers and driver training can have a large impact on AE functionality, some of the
more common examples that have lead to HC faults are:
• Unit operation at low speed/low loads where ATS temperatures are low (city/traffic
conditions)
• Lower ATS temperatures during normal driving in urban routes can result in HC faults where the unit
is unable to complete a driving HC cleanup.

• Driver setting the trailer brake rather than the park brake (most often to avoid idle
shutdown timers)
• Drivers unaware of AE feature may take the following actions:
• Disruption of the safety interlocks
• Turn the ignition off thinking that engine is ‘running away.’
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Chassis & Engine Faults
• Some vehicle faults can also result in AE being disabled, this may be
because they invalidated safety interlocks or that they restrict engine/ATS
operation in specific ways.

• Some examples from both are:
Engine/ATS
- Regen inhibit faults (ex. 2659/0)
- Engine Component faults (Jake Rockers, Jake
Solenoid, EGR valve, Exhaust Gas Flap)
- ATS Component faults (DOC/DPF/SCR
Temperature Sensors)
- PTCAN Communication

Chassis
- Wheel Speed/ABS/VSS Faults
- Service/Park Brake Switches
- Neutral Switch (if equipped)
- J1939 Transmission Gear Signal Interruptions
- ATS Inlet Piping Leaks
- IPPC faults

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Conclusions
To best help with limiting the number of HC faults that are still seen by driver –
1. Repair any engine &/or chassis faults along with completion of campaigns/recalls in a
timely manner.
2. Help drivers be aware of both the automatic/normal operation of the regeneration &
AE processes. Several videos are available on Demand Detroit’s YouTube site that may
help with this:
a)

In the absence of any faults preventing completion, an HC fault is resolvable by driver and
does not require a technician or service visit. The above videos can help familiarize drivers
with the updated technology in today’s trucks.

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