Bulletin No.:

Service Bulletin

Date:

17-NA-374
October, 2020

INFORMATION
Subject:

Brand:

Chevrolet

GMC

Information on Diesel Exhaust Accumulation, Malfunction Indicator Lamp (MIL)
Illuminated - DTC P2463 Set
Model:

Model Year:
from

to

Silverado

2017

2018

Silverado 2500/3500

2019

2021

Silverado 4500HD,
5500HD, 6500HD

2019

2021

Sierra

2017

2018

Sierra 2500/3500

2019

2021

VIN:
from

to

Engine:

Transmission:

L5P
L5D

L5P

Involved Region or Country

North America, Middle East, Israel, Palestine

Information

The following is a list of topics below that are included in the bulletin explaining Diesel
Exhaust System Configuration and DPF Soot Accumulation:
• Reading The Soot Level In % Instead Of Grams
• Service Regeneration vs Regeneration Enable and Drive Cycle
• How To Identify If A Vehicle Idles More Than An Average Vehicle
• How The Regeneration Should Occur
• P2463
• Factors That Contribute To Generating High Levels Of Soot
• If A Customer Asks, “What can I do to reduce the chance of this happening?”

Additional Information
Reading The Soot Level In Percent Instead Of
Grams
There has been a change in the values displayed in
GDS 2. Beginning with the 2017 Silverado/Sierra, the
DPF Soot Accumulation is measured in percent instead
of grams. On vehicles equipped with a L5P engine, the
ECM will not try to perform a regeneration until the DPF
Soot Accumulation increases to approximately 100%. If
the DPF Soot Accumulation increases to 115% and the
system has not been able to regenerate, the “continue
driving” message will be displayed on the DIC. If the
DPF Soot Accumulation increases to 140%, DTC
P2463 will set and will now require a service
regeneration to clean the DPF. You may notice that
there are two soot level readings in GDS2. One that
uses the differential pressure sensor to calculate the
soot in the DPF and one that uses other engine data.
Whichever one of these reaches the threshold first
(100%, 115%, or 140%) wins

Copyright 2020 General Motors LLC. All Rights Reserved.

Service Regeneration vs Regeneration Enable
and Drive Cycle
A Service Regeneration is designed to lower the Soot
Accumulation in the DPF in a very controlled way. It is
not as effective at lowering the soot accumulated in the
DPF as a Regeneration Enable followed by a drive.
Please perform a service regeneration if instructed to
by service information. As a rule of thumb, if a vehicle
has less than 70% DPF Soot Accumulation, do not
perform a service regeneration unless instructed by
Service Information.
Note: If you are concerned about the DPF Soot
Accumulation, perform a regeneration enable and
return the vehicle to the customer.

How To Identify If A Vehicle Idles More Than An
Average Vehicle
Note: Use this formula as a diagnostic aid and in the
administration of a maintenance schedule. It should
NOT be used to determine warranty coverage.

Page 2

October, 2020

Some vehicles may spend a lot of time idling, use the
formula to aid in determining the equivalent mileage
(kilometers):
• Check and record the total engine hours on the
Drivers Information Center (DIC). You may need to
go into the settings menu on the DIC to display the
engine hours.
• Multiply this time by 33 miles or 53 km. This
represents an average speed of 33 MPH or
53KM/H.
• The result should be close to or lower than the
mileage on the odometer.
– Example 1; If a vehicle has 1812.3 engine hours
and 60,837 miles (97,908km) on the odometer,
the engine run time would equate to about
59,806 miles (96,052 km) (1812.3 X 33 =
59,806) (1812.3 X 53 = 96,052)).
Since the calculated mileage is less than the
actual mileage, this vehicle does not spend an
excessive amount of time idling.
– Example 2; If the vehicle has 626.9 engine
hours and 7,269 miles (11,698 km) on the
odometer, the engine run time would equate to
about 20,688 miles (33,226 km) (626.9 X 33 =
20,688 (626.9 X 53 = 33,226)).
Since the calculated mileage is more than the
actual mileage, this vehicle would be considered
a vehicle that idles a lot and this information may
be useful in diagnosing any issues.

How the Regeneration Should Occur
DPF is used to trap the soot generated as a part of the
normal operation of a diesel engine so that it is not sent
into the environment. The process of regeneration is
the vehicle cleaning out the filter so it can trap more
soot. There are four factors that determine when the
ECM will try to perform a regeneration:
1. After approximately 36 gallons (136 L)of fuel used
since the last regeneration.
2. A maximum distance of 800 miles (1287 km) have
been traveled since the last regeneration.
3. A pre-determined number of engine hours since
the last regeneration.
4. A calculated or measured soot mass of 100% in
the particulate filter.
Whichever of the four above criteria is met first will
signal the ECM to perform a regeneration as soon as all
the correct conditions are met. If the ECM cannot
perform a regeneration, the ECM will only look at the
soot mass to determine if the continue driving message
needs to be displayed or the code P2463 is set.
This is the criteria that the ECM is looking for to perform
a regeneration:
• Vehicle in Drive
• BARO sensor 1 is more than 51 kPa (7.4 PSI)
• Engine speed between 500 and 4000 RPM
• Exhaust Gas Temperature Sensor 1 between 100
and 725 C
• Exhaust Gas Temperature Sensor 2 between 95
and 750 C

Bulletin No.: 17-NA-374

•

Exhaust Gas Temperature Sensor 3 between 0
and 750 C
• Exhaust Gas Temperature Sensor 4 between 60
and 750 C
• Exhaust Gas Temperature Sensor 4 between 60
and 850 C
• Engine Coolant Temperature between 50 and
140 C
• Intake air temperature between -70 and 250 C
• Fueling from -1 to 165mm3
• Vehicle speed from -1 to 160 km/hr
• No active DTC related to EGR, Indirect injector, or
Throttle (boost)
This vehicle does not have a soot level sensor to
determine how much soot is in the DPF. Instead, it uses
algorithms to calculate the soot mass. These
algorithms rely on the fact that the vehicle is otherwise
healthy to accurately determine how much soot is in the
filter.

P2463
When this code sets, the ECM will no longer try to
perform a driving regeneration and the vehicle will
require the more controlled service regeneration. If this
is the only code that set, we need to try to figure out
why it set. Since this is the last component in the
exhaust, there are quite a few different things that can
cause this code to set. I have even fixed vehicles from
setting this code by replacing the air filter or replacing
TMAP sensor. Here are a few other things that can
cause this code to set:
⇒ Driving style like binary driving with a high
frequency
⇒ The driver Ignoring the keep driving messages
⇒ Leaks from intake or exhaust system
⇒ Poor fueling in the engine
⇒ Contaminated or bad fuel
⇒ Externally damaged or worn components.
⇒ Loose or improperly installed components

Factors That Contribute To Generating High
Levels Of Soot
This is a list of things to look for:
– Charge air cooler (CAC) and Air induction system
leaks. Perform the Full System Air Leak Test and
then the Induction System Smoke Test. Refer to
Charge Air Cooler Diagnosis – refer to Charge Air
Cooler Diagnosis (Full System Air Leak Test).
PIP5684, and PIP5468.
– A restricted air filter. Refer to PIP5489.
– Exhaust system leaks. An exhaust system leak may
cause inaccurate Exhaust Gas Temperature sensor
or Exhaust Pressure Differential sensor values Refer to Exhaust Leakage.
– Failed, intermittent, improperly installed, mis wired,
or loose Exhaust Gas Temperature sensors will
cause inaccuracies in the soot model – Look at all
temperature sensors when the vehicle is cold to
make sure that they read close to each other.

Bulletin No.: 17-NA-374

October, 2020

– Improperly routed differential pressure lines—The
exhaust differential pressure line should have a
continuous downward gradient without any sharp
bends or kinks from the sensor to the DPF.
– Leaks or internal restrictions from the Exhaust
Pressure Differential sensor lines.
– A skewed or shifted Exhaust Pressure Differential
sensor. A sensor that is skewed will cause
inaccuracies in the soot model.
– A cracked or damaged MAF sensor housing.
– A skewed, stuck in range, or slow responding MAF
sensor. Inspect the MAF sensor for contamination.
Refer to DTC P0101-P0103.
– Indirect Fuel Injector leaking or restricted—Refer to
Exhaust Aftertreatment Fuel Injector Diagnosis.
– Externally damaged or worn components.
– Loose or improperly installed components.
– Water in fuel contamination—Refer to
Contaminants-in-Fuel Diagnosis.
– Engine mechanical condition, for example low
compression. Refer to Symptoms - Engine
Mechanical.
– Vehicle Modifications

Page 3

If A Customer Asks, “What can I do to reduce
the chance of this happening?”
When the “Continue Driving“ message is displayed,
continue driving safely at a steady speed as close to
the posted speed limit as possible, until the message
turns off. This can take up to 30 minutes.
Drive with cruise control when possible. This should
help with fuel economy as well as help the engine burn
cleaner resulting in less regenerations.
Drive with a steady foot. Lots of tip in and tip outs every
few seconds or aggressive driving with frequent WOTs
will start and stop the turbo. This will cause the system
to generate a lot of soot.
When descending an incline, use tow haul mode to
help with the ability of the vehicle to perform a
regeneration.
The use of the grade brake on declines will also help
adjust the gearing to help allow the vehicle to perform a
regeneration. NOTE: on 2020 model year vehicles the
grade brake may not be as noticeable as in vehicles
built prior to or after this model year. The use of the
grade brake will help the vehicle be able to perform a
regeneration.

Parts Information
No parts are required for this repair.
Version

5

Modified

Revised March 21, 2018 - Update Information section.
Revised June 26, 2019 – Added 2019 and 2020 Model Years to 2500/3500 models.
Revised July 22, 2020 - Revised Information and Additional Information sections.
Revised October 16, 2020 - Added 2021 Model Years to 2500/3500 models and added
2019–2021 Silverado 4500, 5500 and 6500 HD Models.

GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these
technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper
service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a
job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your
vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the
information.

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