Manufacturer communication — 2006 GMC YUKON DENALI XL

• 2020 and prior GM passenger cars and trucks.

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  2020 and Prior GM Passenger Cars and Trucks

• Customers report various issues related to high or low speed data bus traffic.

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  Customers may comment on various issues with their vehicle related to high or low speed data bus traffic.

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

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

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

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

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

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

• Gauge readings may be erratic or displays may flicker.

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  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.

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  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 could be caused by an open connection on the HSCAN bus, for example a device that connects to only one CAN +.

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  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.

Steps to confirm (in the document’s order)

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

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   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.

2. A device with a secondary DLC connector can be hidden with its harness, so the technician may not notice that the diagnostic connector is not in the factory location.

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   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.

Repair

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

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  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.

Caution

• The customer may have removed the device for use in another vehicle while this one is in for service.

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  These devices may be removed by the customer for use in another vehicle while theirs is brought in for service.