{"id":19820,"date":"2026-09-16T05:00:17","date_gmt":"2026-09-16T09:00:17","guid":{"rendered":"https:\/\/gm-techlink.com\/?p=19820"},"modified":"2026-09-16T14:39:28","modified_gmt":"2026-09-16T18:39:28","slug":"tcsc-top-issues-this-week","status":"publish","type":"post","link":"https:\/\/gm-techlink.com\/?p=19820","title":{"rendered":"TCSC Top Issues This Week"},"content":{"rendered":"

The Techline Customer Support Center (TCSC) is available to help dealerships with diagnostic and programming issues related to Techline Connect (TLC) and the Service Programming System (SPS).<\/p>\n

TCSC has now released its latest tips to help technicians when using Techline Connect applications. (Fig. 1) Look for the latest information on TechLink each week.<\/p>\n

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\"\"Fig. 1<\/strong><\/p>\n

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To get the most out of Techline Connect, be sure to review the following items before making a call to TCSC.<\/p>\n

The following information covers current issues and trends facing dealerships as of September 16, 2026.<\/strong><\/p>\n

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WEEKLY ISSUES<\/strong><\/p>\n

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1. GCUS Article: 22795 – Service Programming System (SPS) Delta Programming – New Selection<\/strong><\/p>\n

On August 24, 2026, there was an update to SPS in Techline Connect (TLC). The update changes how a technician programs certain radios in SPS. This change is an additional selection called \u201cDelta Programming\u201d and is being made to simplify programming by reducing steps and eliminating the USB drive requirement. For now the original selections will also remain in place. This will also be available in Vehicle Wide Programming (VWP) to further streamline the process.<\/p>\n

At this point, the option will only be available on MY2026 T1 SUVs for IVD and IVE radios.\u00a0 More vehicle platforms and radios will be added in the future. Please refer to SI for updated programming instructions for these vehicles.<\/p>\n

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2. 2019-2022 Trax Replacement IPC Programming Fails E-4491 \u2013 #PIC6659 <\/strong><\/p>\n

There is now a resolution for any 2019-2022 Trax model failing replacement IPC programming with E-4491 errors (commonly: x, B0, 85) The current fix is to have the dealership order a pre-reprogrammed cluster from Specmo and then run the IPC set-up procedure in SPS2 when the cluster is received.<\/p>\n

Refer to #PIC6659 (Document ID: 7200717) for more information.<\/p>\n

Note: Please have the vehicle odometer and repair order documented.<\/p>\n

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3. Immobilizer Learn \u201cNext\u201d Button may be Grayed Out during SPS2 Programming<\/strong><\/p>\n

Users report when performing the Z1 Immobilizer Learn, the \u201cnext\u201d button may be grayed out and they are unable to proceed with the learn. This can occur with any vehicle.<\/p>\n

If you are experiencing this issue, please contact TCSC. Note: TCSC contact instructions are at the bottom of this document.<\/p>\n

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4. K73 OnStar\/Telematics Module E-4393 Programming <\/strong><\/p>\n

Users may receive E-4393 programming errors when programming K73 OnStar\/Telematics Module – Delta Programming<\/strong>. This error may occur on any vehicle.<\/p>\n

If you are experiencing this issue, please contact TCSC. Note: TCSC contact instructions are at the bottom of this document.<\/p>\n

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5. K299 Audio\/Video Interface Rear Module E-4393 Programming Error on 2026 T1 SUVs<\/strong><\/p>\n

Users may receive E-4393 programming errors when programming the K299 Audio Video Interface Rear Module \u2013 Rear Module Delta (Step 2)<\/strong>. If you encounter this error when programming, select the Do Not Use \u2013 Unsupported Function<\/strong> option for this module to successfully complete programming.<\/p>\n

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6. Incorrect Radio Listed in EPC for IVD Radio on 2024-2025 Silverado EV<\/strong><\/p>\n

The Electronic Parts Catalog (EPC) is directing dealers to order PN 86295933, which is not a compatible IVD radio with the MY24 and MY25 Silverado EV.<\/p>\n

The compatible part number is 86295936. However, there is not any current stock of these parts. GM is working to replenish the stock, but there is not an ETA currently of when these parts will be available.<\/p>\n

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7. EPC Showing Incorrect Radio Hardware for 2025 Blazer EV with IVD Radio<\/strong><\/p>\n

Users report that the Electronic Parts Catalog (EPC) is directing to an incompatible part for the 2025 Blazer EV with the IVD radio.<\/p>\n

PN 85852385 is not compatible with the 2025 Blazer EV. Please order PN 85791702 instead.<\/p>\n

GM is working on correcting the EPC to show the correct hardware.<\/p>\n

Note: If you are unable to place an order for PN 85791702, please reach out to the dealership\u2019s Regional Operations Manager.<\/p>\n

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8. 2021 Tahoe, Suburban, Yukon, Escalade, Corvette, Envision, CT4, CT5 Unable to Complete SDAC \u2013 #PIT6507<\/strong><\/p>\n

There is currently a known issue affecting some 2021 model year vehicles where the SDAC (Serial Data Authentication Configuration) may fail. The radio, IPC, or Telematics (OnStar) modules may be the cause of these failures.<\/p>\n

DO NOT REPLACE THE MODULE.<\/strong> This is a known SPS issue and the current workaround is to reprogram the SDGM for the latest released calibrations and retry the programming event. If this does not resolve the issue, please refer to #PIT6507 for instructions on disconnecting the SDGM X3 connector and for more information on affected vehicles.<\/p>\n

Note: The X3 connector is very delicate. Please handle it with care.<\/p>\n

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9. 9G8 (DRL\/AHL Disable), SK4 (Engine Idle Timeout), UTQ (Content Theft), BCN (Retail Locking) and 6N6 (Rear Window Disable) Not Yet Available on 2026 Vehicles<\/strong><\/p>\n

Calibrations for RPOs 9G8, SK4, UTQ, BCN and 6N6 are not yet available for model year 2026 vehicles but are planned to be released. However, there is not currently an ETA.<\/p>\n

Note: RPO SK4 calibrations are now available for T1 Trucks (Silverado, Sierra). T1 SUV (Tahoe, Suburban, Yukon, Escalade) is still being worked on.<\/p>\n

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COMMON ISSUES AND HELPFUL INFORMATION<\/strong><\/p>\n

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1. ECM\/Radio\/IPC Part Missing from SPS2 Part Dropdown<\/strong><\/p>\n

When performing IPC Graphics programming, Radio USB, or ECM programming, you may be prompted in SPS2 to select \u201cService Hardware.\u201d<\/strong> However, this is misleading.<\/p>\n