GMC Yukon XL 2000–2006

▸ELECTRICAL SYSTEM1

1. Manufacturer communication2005–2006 GMC YUKON XL 2500 ・ 2024-05-16(10 earlier editions of this document folded here)

   Aftermarket ALDL/DLC Interface Device Concerns

   1. 1Fault

      • Warning light
      • C0561 (general documents only)
      • U0100 (general documents only)
      • U0101 (general documents only)
      • U186B (general documents only)
      • U1862 (general documents only)
      • Customers report various issues related to high or low speed data bus traffic.
      • Bus or LAN traffic may stay active, leading to a discharged vehicle battery.
      • C0561 stored in the EBCM, leading to a traction control issue.
      • SES, MIL or CEL light on with numerous communication DTCs such as U0100, U0101, U186B and U1862.
      ↓→

   2. 2Finding the cause

      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.
      • Many of the problems could come from an open connection on the HSCAN bus; a device that connects to only one CAN + causes bus errors and erratic ECU behavior.

      Steps to confirm (in the document’s order)

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

   3. 3Correction

      Repair

      1. If SI diagnostics do not find the source and the device is available, try to duplicate the condition, then remove the device to see whether the condition is eliminated.
      2. If removing the DLC interface device resolves the concern, tell the customer the result and that they should work with the device's supplier for further resolution.

      Caution

      • The device and the rest of its harness can be hidden out of sight, and the technician may not notice that the diagnostic connector is not in the factory location.
   Read the sentences of the record

   From the manufacturer’s document

   • Applies to：2025 and prior GM passenger cars and trucks (including BrightDrop).
   • Applies to：The bulletin is written with a focus on full size trucks, full size vans and other fleet vehicles, but could apply to any vehicle.
   • Condition：Customers report various issues related to high or low speed data bus traffic.
   • Condition：Bus or LAN traffic may stay active, leading to a discharged vehicle battery.
   • Condition：C0561 stored in the EBCM, leading to a traction control issue.
   • Condition：SES, MIL or CEL light on with numerous communication DTCs such as U0100, U0101, U186B and U1862.
   • Confirm：If normal SI diagnostics find no other root cause, check for a device plugged into the ALDL or Data Link Connector (DLC) for tracking and/or maintenance interval scheduling.
   • Cause：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.
   • Cause：Many of the problems could come from an open connection on the HSCAN bus; a device that connects to only one CAN + causes bus errors and erratic ECU behavior.
   • Caution：The device and the rest of its harness can be hidden out of sight, and the technician may not notice that the diagnostic connector is not in the factory location.
   • Repair：If SI diagnostics do not find the source and the device is available, try to duplicate the condition, then remove the device to see whether the condition is eliminated.
   • Repair：If removing the DLC interface device resolves the concern, tell the customer the result and that they should work with the device's supplier for further resolution.

   Open the manufacturer’s document (PDF) ↗ The points above were read from this document.

   Remedy

   The intent of this service bulletin is to identify aftermarket ALDL or DLC interface devices as potential sources for causing multiple customer concerns that do not have other diagnostic methods to identify them.