Bulletin No.
:   13-08-116-001E
                       Service Bulletin                                                         Date:    July, 2019
                                                          TECHNICAL
Subject:             Aftermarket ALDL or DLC Interface Devices Causing Multiple Issues
Models:              2020 and Prior GM Passenger Cars and Trucks
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 2020 Model Year and remove text from some
                    graphics. Please discard Corporate Bulletin Number 13-08-116-001D.
Condition                                                        •   SES, MIL or CEL light set and numerous DTC
                                                                     communication codes such as U0100, U0101,
Customers may comment on various issues with their                   U186B and U1862.
vehicle related to high or low speed data bus traffic.
These concerns may be widely varied, but some of the             •   Diesel power-up devices causing no power in
known issues are listed below.                                       4WD low range.
The information contained in this bulletin is not meant          •   Erratic electric power steering boost potentially
to single out any one device or symptom, but to provide              associated with codes U2109, U2107, U2100,
additional information that may be useful for diagnosing             B1325, C0000.
issues that do not have other diagnostic methods to              •   Battery run down
identify the root cause.                                         •   Service Tire Pressure Monitoring (TPM) system
Note: This bulletin is being written with a focus on full            light illuminated.
size truck and full size van along with other fleet                  – Cannot relearn TPM
vehicles, but could apply to any vehicle.                        •   Specific to Hybrids:
                                                                     – Reduced propulsion power message.
Known Symptoms (not specific to any one device)                      – Service high voltage charging system message.
 • The radio may not shut off after shutting down
   vehicle.                                                    Cause
 • Bus or LAN traffic may stay active leading to a             If nothing else can be identified as the root cause of the
   discharged vehicle battery.                                 issue after normal diagnostics as found in SI, check for
 • Problems reprogramming modules either because               a device plugged into the Assembly Line Diagnostic
   of interference or the device will not allow the bus        Link (ALDL) or Data Link Connector (DLC) for tracking
   to power down.                                              and/or maintenance interval scheduling. Monitoring
                                                               devices, along with other electronic accessories such
 • ONSTAR® may lose the ability to provide                     as aftermarket cruise control, or police speed checking
   diagnostic data.                                            devices (RADAR or LIDAR) may cause one or more of
 • Various engine and transmission performance                 the concerns listed above.
   issues with SES light set.                                  Many of the problems described could be caused by an
 • Intermittent driveability issues.                           open connection on the HSCAN bus. Example: if the
 • Reduced power message and codes.                            device only makes connection with one CAN +, then it
                                                               will cause bus errors and erratic ECU behavior.
 • Stabilitrak® message and codes.
                                                               These devices may be removed by the customer for
 • C0561 stored in the EBCM leading to a traction              use in another vehicle while theirs is brought in for
   control issue.                                              service. The intent of this bulletin is to identify a
 • No high speed LAN communication along with                  potential source of concerns that do not have other
   various communication U-codes.                              diagnostic methods to identify them. The examples
 • Transmission may not shift for one key cycle (TCM           below illustrate some of the devices encountered.
   in default mode).
 • Erratic gauge readings or flickering displays.
Copyright 2019 General Motors LLC. All Rights Reserved.
Page 2                                               July, 2019          Bulletin No.: 13-08-116-001E
Examples:                                                         Aftermarket Device at ALDL
The monitoring device examples are not specific to any
one design, and styles will vary.
     Device W/Secondary DLC Connector
                                                                                                3346648
                                                                  Aftermarket Device Switch
                                                   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.
Pedal Mounted Aftermarket Device Interface
                                                                                                3346650
                                                   3346646
Bulletin No.: 13-08-116-001E              July, 2019                                                Page 3
        Monitoring Device Example                 Fleet Tracking Module Plugged Into the DLC
                                        3346651                                                        3346654
Fleet Tracking Device Interface (May Include      Correction
         Rental and Lease Vehicles)               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.
                                                  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
                                        3346652   documented correctly stating factual information on
                                                  what alteration or product was identified on the vehicle.
Page 4                                                                            July, 2019                                  Bulletin No.: 13-08-116-001E
Warranty Information                                                                           If a claim is submitted to GM, follow all existing
                                                                                               guidelines within the Service Policies & Procedures
If ALDL interface devices are suspected as the root                                            and GWM User Manual, GlobalConnect Messages,
cause for a customer's concerns, submit a claim using                                          Bulletins or any other communication format.
the 0600014 labor operation to document the concern
as detailed in the latest version of Corporate Bulletin
                                                                                                     Labor                        Description           Labor
Number 09-00-89-016 “Warranty Administration - Labor                                                Operation                                           Time
Operation 0600014 - Suspected Tampering or Vehicle
Modifications, including submitting the claim under the                                              0600014                  Suspected Tampering       0.2 hr
appropriate labor operation and selecting the Customer
Enthusiasm indicator in Global Warranty Management.
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                       WE SUPPORT VOLUNTARY
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                     TECHNICIAN
vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the                              CERTIFICATION
information.