PIT5985C
Service Bulletin Details
Public Details for: PIT5985C
This preliminary information communicates diagnostic tips on how to resolve a issues with vehicles that will not power up after a can bus 2 issue, lightning strike, or a failed over the air update.
- 2024 - 2023 - 2022 - 2021 - 2020 -
Models from 2024
Models from 2023
Models from 2022
Models from 2021
2021 BUICK ENVISION |
2021 CADILLAC CT4 |
2021 CADILLAC CT5 |
2021 CADILLAC ESCALADE ESV |
2021 CHEVROLET CORVETTE |
2021 CHEVROLET SUBURBAN |
2021 CHEVROLET TAHOE |
2021 GMC YUKON XL |
Bulletin No.: PIT5985C Published date: 11/17/2023 Preliminary Information PIT5985C Diagnostic Tip: No Start/ Ignition Will Not Turn ON/ No Power Due To A CAN bus 2 Issue/Lightning Strike/ Failed Over The Air Update Models Brand: Model: Model Years: VIN: from to Engine: Transmissions: Buick Envision 2021 - 2023 All All All All Brightdrop EV600 2022 All All All All Cadillac CT4 2020 - 2024 All All All All Cadillac CT5 2020 - 2024 All All All All Cadillac Escalade Models 2021 - 2024 All All All All Cadillac LYRIQ 2023 - 2024 All All All All Cadillac XT4 2024 All All All All Chevrolet Blazer EV 2024 All All All All Chevrolet Colorado 2023 All All All All Chevrolet Corvette 2020 - 2024 All All All All Chevrolet Silverado 1500 New (RPO J22, VIN Digit 12 = A or D) 2022 All All All All Chevrolet Silverado 1500 2023 - 2024 All All All All Chevrolet Silverado 2500HD/3500HD 2024 All All All All Chevrolet Silverado EV 2024 All All All All Chevrolet Suburban 2021 - 2024 All All All All Chevrolet Tahoe 2021 - 2024 All All All All GMC Canyon 2023 All All All All GMC HUMMER EV 2022 - 2024 All All All All GMC HUMMER EV SUV 2024 All All All All GMC Sierra 1500 New (RPO J22, VIN Digit 12 = A or D) 2022 All All All All GMC Sierra 1500 2023 - 2024 All All All All GMC Sierra 2500HD/3500HD 2024 All All All All GMC Yukon Models 2021 - 2024 All All All All Involved Region or Country North America Some technicians may experience one or more of the following concerns: Condition 1. No Start 2. Vehicle will not crank 3. Vehicle will not enter into Key On, Engine O mode (Service Mode) 4. Vehicle's Instrument Panel Cluster will not Illuminate 5. Vehicle will not shut O . In addition to the above concerns, when using GDS2 to connect to the vehicle, the pop up message seen below will be displayed, prompting to turn the ignition on, but the ignition can not be turned on. In some cases, after several ignition button presses, the ignition may turn on. Then, the customer or dealer technician may notice that blower motor turns on at a higher speed and then the ignition will not be able to be turn O . Cause This may be caused by either an issue with Can Bus 2, the vehicle received an "Over The Air" (OTA) update that has failed/ or the vehicle's electrical system was damaged by a voltage spike such as a lightning strike or an incorrect jump start procedure. Correction: The following are some diagnostic tips to help isolate the concern: 1) Dealership technicians will notice that they are unable to access GDS data to review DTC's or check the network communication status. They may experience the following pop up box, shown below, and will be unable to get past this screen. You will need to keep hitting the continue button 5-6 times and then it will allow you to get past this screen and then it will be possible to go into vehicle diagnostics to check DTC's and CAN bus status. 2) Next, use GDS2 Network Communication Status and check each CAN bus (1-8) to determine which modules are communicating and which modules are not communicating. This is similar to the Detected State feature of the Data Bus Diagnostic Tool (DBDT), but the DBDT will not work on these models. The GDS2 Network Communication Status can be found by following this GDS2 path: Vehicle Diagnosis/Vehicle Communication Diagnostics/Network Communication Status. Go through each CAN bus tab (CAN bus 1 -8) and note/document the communication status of each module. When switching from tab to tab you may want to wait 25-30 seconds to see if modules show up. The picture below shows an example of CAN bus 2 status. Diagnosis and repair any modules that are not communicating. If a module fails to communicate due to a failed OTA, rst try to recover the module by reprogramming the module using SPS. Then clear all DTC's and recheck for concern. 3) If after all modules are communicating and you continue to have issues or current DTC: U1962, then perform a Serial Data Authentication Con guration (SDAC), which is located on the SPS controller screen in the SPS, shown below. This will have to be completed so each module recognizes each other on their respective data buses. 4) If the SDAC fails, it will attempt to run a total of 3 times. If it fails after the third attempt, an additional screen will pop up, identifying which module is causing the SDAC to fail. Be patient, as this pop-up screen may take up to 25-30 seconds to appear. Take a picture of the pop-up screen and reference the latest version of PIT5832. 5) If the SDAC passes and a labor code is generated, make sure to clear all the U codes that are current or the vehicle still may not start. Additional SI Keywords U1960 U1961 U1962 Version History Version Modi ed 4 02/28/2023 - Created on 03/06/2023- Updated to add Brightdrop Model EV600 08/30/2023- Update to add 2024 models years and add Blazer EV and 2024 Silverado and Sierra HD models 11/17/2023- Updated to add model years and new models that have added VIP © 2023 General Motors. All Rights Reserved.