2021-2022 Audi Q5/SQ5 Ignition Cannot Be Turned On TSB

Symptoms

Owners of certain 2021-2022 Audi Q5 and SQ5 models may experience a critical issue where the "vehicle cannot be started or the ignition cannot be turned on." This problem prevents the vehicle from operating and can also hinder diagnostic efforts, as the vehicle may be "unable to be scanned using the ODIS tester."

Technicians investigating this condition often find that "fuse S164 had been blown." This specific symptom points to an electrical fault that prevents the vehicle's ignition system from functioning correctly.

Technical Background

According to Audi TSB 2064805/1, the root cause of the blown fuse S164 is typically a short circuit to ground. This short circuit occurs in the wiring harness located in the driver's footwell area, specifically on the front left side. An improved harness routing has been implemented in production to prevent this issue in newer vehicles.

Important Warnings

It is crucial to understand that fuse S164 is not replaceable as a standalone component; the entire central protection assembly, part number 80A 915 459, is required for replacement. For this reason, the underlying short circuit must be located and repaired BEFORE the fuse assembly is replaced. Failing to address the short circuit first will result in the new fuse blowing immediately.

Additionally, owners should note that if their vehicle is outside of its warranty period, this Technical Service Bulletin is provided for informational purposes only. Any repairs performed would typically be at the owner's expense.

Repair Procedure Summary

Addressing the issue of an "Audi Q5 ignition cannot be turned on" involves a detailed repair process outlined in TSB 2064805/1. The procedure begins by gaining access to the fuse holder located beneath the driver's footrest. This requires removing the driver's seat, footrest cover, lower A-pillar trim, and floor mat, then folding back the carpet to expose the fuse box.

Once the area is accessible, technicians must carefully inspect the red wire leading to control unit J329 (terminal 30) and the black wire on J329 (terminal 15) for any signs of damage or chafing. If any wire is found to be damaged, it must be repaired using the specialized wire harness repair kit, VAS 1978B.

After all necessary wire repairs are completed, additional steps are required to prevent future occurrences. The 30mm section of the harness must be wrapped with harness tape (N 107 290 02). The harness is then re-routed to prevent further chafing and secured with a cable tie (5M0 971 838). Finally, all stored fault codes must be cleared to complete the repair.

Required Parts and Tools

To perform this repair, the following parts and tools are specified:

• Central protection: 80A 915 459
• Harness tape: N 107 290 02
• Cable tie: 5M0 971 838
• Wire harness repair kit: VAS 1978B
• Fasteners, Bolts, Nuts, and Screws: As needed per the repair manual (See ETKA/ELSA)

Warranty Information

This repair is covered under Audi's warranty program for eligible vehicles. The claim type is 110 for vehicles up to 48 months or 50,000 miles. For Certified Pre-Owned (CPO) vehicles, the claim type is G10, requiring owner verification. The Service Number for this bulletin is 9709, and the Damage Code is 0025.

Labor operations associated with this repair include:

• Remove and install front seat: 7201 1900
• Release and secure front floor covering (including removing and installing floor mat, footrest, and A-pillar trim): 7041 0999
• Modify central wiring harness: 9709 4999
• Repair central wiring harness (if needed): 9709 41XX

Diagnostic time for this issue is recorded under GFF (0150 0000). A road test after the service procedure (0121 0004) is allotted 10 time units.

Source: NHTSA ID 10203175