Manufacturer communication — 2006 GMC YUKON DENALI XL

• Applies to 2024 and earlier GM passenger cars and trucks.

  the passage

  Models: 2024 and Prior GM Passenger Cars and Trucks

• The bulletin is written with a focus on full size trucks, full size vans and other fleet vehicles, but could apply to any vehicle.

  the passage

  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.

• Bus or LAN traffic may stay active, leading to a discharged vehicle battery.

  the passage

  Bus or LAN traffic may stay active leading to a discharged vehicle battery.

• DTC C0561 may be stored in the EBCM, leading to a traction control issue.

  the passage

  C0561 stored in the EBCM leading to a traction control issue.

• The SES, MIL or CEL light may be set with numerous communication DTCs such as U0100, U0101, U186B and U1862.

  the passage

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

• The transmission may not shift for one key cycle, with the TCM in default mode.

  the passage

  Transmission may not shift for one key cycle (TCM in default mode).

• Gauge readings may be erratic or displays may flicker.

  the passage

  Erratic gauge readings or flickering displays.

Possible causes

• Monitoring devices and other electronic accessories such as aftermarket cruise control or police speed checking devices (RADAR or LIDAR) may cause one or more of the listed concerns.

  the passage

  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.

Steps to confirm (in the document’s order)

• If normal SI diagnostics identify no root cause, check for a device plugged into the ALDL or Data Link Connector (DLC) for tracking and/or maintenance interval scheduling.

  the passage

  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.

Repair

1. If the device is available, try to duplicate the condition, then remove the device to see whether the condition is eliminated.

   the passage

   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.

2. If the condition is not eliminated with the device removed, continue diagnosing the vehicle with the appropriate Service Information.

   the passage

   If the condition is not eliminated with the device removed, continue diagnosing the vehicle with the appropriate Service Information.

Caution

• A device with a secondary DLC connector can be hidden out of sight with its harness, and the technician may not notice that the diagnostic connector is not in the factory location.

  the passage

  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.