Bulletin No.: 13-08-116-001J

Service Bulletin

Date: April, 2024

TECHNICAL
Subject:

Aftermarket ALDL or DLC Interface Devices Causing Multiple Issues

Models:

2025 and Prior GM Passenger Cars and Trucks (including BrightDrop)

Attention:

This bulletin also applies to any of the above models that may be Export
from North America vehicles.

This bulletin has been revised to add the 2025 Model Year, BrightDrop Models
and second Important statement. Please discard Corporate Bulletin Number
13-08-116-001I.
Condition
Important: Service agents must comply with all
International, Federal, State, Provincial, and/or
Local laws applicable to the activities it performs
under this bulletin, including but not limited to
handling, deploying, preparing, classifying,
packaging, marking, labeling, and shipping
dangerous goods. In the event of a conflict
between the procedures set forth in this bulletin
and the laws that apply to your dealership, you
must follow those applicable laws.
Important: This technical service bulletin (TSB) can
only be completed by BrightDrop dealers or BrightDrop
certified repair facilities who have met all BrightDrop
specific training, tool, and equipment requirements.
Repairs must be performed by a technician who has
successfully completed the required training.
Customers may comment on various issues with their
vehicle related to high or low speed data bus traffic.
These concerns may be widely varied, but some of the
known issues are listed below.

• Bus or LAN traffic may stay active leading to a
discharged vehicle battery.
• Problems reprogramming modules either because
of interference or the device will not allow the bus
to power down.
• ONSTAR® may lose the ability to provide
diagnostic data.
• Various engine and transmission performance
issues with SES light set.
• Intermittent driveability issues.
• Reduced power message and codes.
• Stabilitrak® message and codes.
• C0561 stored in the EBCM leading to a traction
control issue.
• No high speed LAN communication along with
various communication U-codes.
• Transmission may not shift for one key cycle
(TCM in default mode).
• Erratic gauge readings or flickering displays.

The information contained in this bulletin is not meant
to single out any one device or symptom, but to provide
additional information that may be useful for diagnosing
issues that do not have other diagnostic methods to
identify the root cause.

• SES, MIL or CEL light set and numerous DTC
communication codes such as U0100, U0101,
U186B and U1862.

Note: This bulletin is being written with a focus on full
size truck and full size van along with other fleet
vehicles, but could apply to any vehicle.

• Erratic electric power steering boost potentially
associated with codes U2109, U2107, U2100,
B1325, C0000.

• Diesel power-up devices causing no power in 4WD
low range.

• Battery run down
Known Symptoms (not specific to any one device)
• The radio may not shut off after shutting down
vehicle.

Copyright 2024 General Motors. All Rights Reserved.

• Service Tire Pressure Monitoring (TPM) system
light illuminated.
– Cannot relearn TPM
• Specific to Hybrids:

Page 2

April, 2024

− Reduced propulsion power message.

Bulletin No.: 13-08-116-001J

Pedal Mounted Aftermarket Device Interface

− Service high voltage charging system message.

Cause
If nothing else can be identified as the root cause of the
issue after normal diagnostics as found in SI, check for
a device plugged into the Assembly Line Diagnostic
Link (ALDL) or Data Link Connector (DLC) for tracking
and/or maintenance interval scheduling. Monitoring
devices, along with other electronic accessories such
as aftermarket cruise control, or police speed checking
devices (RADAR or LIDAR) may cause one or more of
the concerns listed above.
Many of the problems described could be caused by an
open connection on the HSCAN bus. Example: if the
device only makes connection with one CAN +, then it
will cause bus errors and erratic ECU behavior.
These devices may be removed by the customer for
use in another vehicle while theirs is brought in for
service. The intent of this bulletin is to identify a
potential source of concerns that do not have other
diagnostic methods to identify them. The examples
below illustrate some of the devices encountered.

3346646

Aftermarket Device at ALDL

Examples:
The monitoring device examples are not specific to any
one design, and styles will vary.
Device W/Secondary DLC Connector

3346648

3346643

This device has another DLC connector on it. The rest
of the harness along with the device can be placed out
of sight hidden from the technician, who may not notice
the diagnostic connector is not in the factory location.

Bulletin No.: 13-08-116-001J

April, 2024

Aftermarket Device Switch

Page 3

Fleet Tracking Device Interface (May Include Rental
and Lease Vehicles)

3346650

Monitoring Device Example

3346652

Fleet Tracking Module Plugged Into the DLC

3346651
3346654

Correction
If SI diagnostics do not identify the source of the issue
and if the device is available, attempt to duplicate the
condition, and then remove the device to determine if
the condition is eliminated.
If the customer’s concern is resolved by removing the
DLC interface device, inform the customer of the
results, and that they should work with the supplier of
the device for further resolution.
If the condition is not eliminated with the device
removed, continue diagnosing the vehicle with the
appropriate Service Information.

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April, 2024

Bulletin No.: 13-08-116-001J

Parts Information
There should not be any parts required. If on the rare
occasion parts appear to have been damaged by the
device or the installation of the device, this would not
be a defect covered under the New Vehicle Limited
Warranty. For more information on Non-General Motors
Parts & Equipment and Original Equipment Alterations,
please refer to Article 1.2.2.12 of the Warranty Policy
Information Manual. The repair order must be
documented correctly stating factual information on
what alteration or product was identified on the vehicle.

Warranty Information
If ALDL interface devices are suspected as the root
cause for a customer's concerns, submit a claim using
the 0600014 Labor Operation to document the concern
as detailed in the latest version of Corporate Service
Bulletin Number #09-00-89-016: Warranty Administration - Labor Operation 0600014 - Suspected
Tampering or Vehicle Modifications, including
submitting the claim under the appropriate labor
operation and selecting the Customer Enthusiasm
indicator in Global Warranty Management.
If a claim is submitted to GM, follow all existing guidelines within the Service Policies & Procedures and
GWM User Manual, GlobalConnect Messages,
Bulletins or any other communication format.
Labor Operation

Description

Labor
Time

0600014

Suspected Tampering

0.2 hr

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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