2025 Audi Q5/SQ5 Door Cannot Be Opened From Outside

Owners of certain 2025 Audi Q5 and SQ5 models may encounter a frustrating issue where one of their vehicle's doors intermittently refuses to open from the outside. This problem, detailed in Technical Service Bulletin (TSB) 2079914/2, specifically describes a condition where the door can always be opened from the inside, and all other doors function normally from the outside. Interestingly, once the interior door handle of the affected door has been pulled, the door can then be opened again from the outside for a period.

This TSB, initially published on November 10, 2025, and revised on December 18, 2025, provides comprehensive diagnostic and repair procedures for technicians to address this specific door opening malfunction. The bulletin highlights that the underlying cause is typically a software or hardware issue affecting the door control unit or the door lock mechanism. Addressing the issue of an Audi Q5 door cannot be opened from the outside requires a systematic approach to diagnosis.

Symptoms

The primary symptom reported by vehicle owners is that "One of the doors cannot be opened intermittently from the outside. It can always be opened from the inside. All other doors can be opened from the outside. Once the interior door handle of the door in question has been pulled out, it can be opened again from the outside." This intermittent behavior suggests a nuanced problem rather than a complete mechanical failure.

Fault Codes / DTCs

In many cases, this door opening issue is accompanied by a specific diagnostic trouble code (DTC) stored in the vehicle's event memory. Technicians should look for the entry:

• B122D29 - Lock unit for central locking - implausible signal - passive/intermittent

This DTC indicates an implausible signal from the central locking unit, pointing directly to a potential problem with the door lock or its associated control unit. However, the TSB also provides guidance for situations where this specific DTC is not logged.

Diagnosis / Trigger Conditions

Diagnosing the root cause of why an Audi Q5 door cannot be opened from the outside involves several steps. First, technicians will attempt to reproduce the customer's complaint. If the issue is present, the next step depends on whether DTC B122D29 is logged.

If DTC B122D29 is present, the technician will proceed to check the part version of the door lock installed on the faulty door. This can be done without removing the component, as illustrated in Figure 2 of the TSB, which shows the part version clearly visible on the door lock assembly. The part version is crucial for determining the next diagnostic steps.

An important warning is issued regarding incorrect operation that can mimic a fault: "When opening the doors, care must be taken not to touch the sensor on the exterior door handle at the same time, e.g. with the thumb, otherwise the vehicle will lock again (Q6 e-tron example in figure 1)." This highlights the sensitivity of the convenience key system and helps differentiate between a genuine fault and user error.

Repair Procedure Summary

The repair procedure outlined in TSB 2079914/2 is conditional, depending on the presence of DTC B122D29 and the door lock's part version. The overall goal is to either update software, replace the door lock, or replace the door control unit.

Scenario 1: DTC B122D29 is logged

1. Check Door Lock Part Version: Inspect the part version of the door lock on the faulty door. This is a critical step that dictates the subsequent diagnostic path.
2. If Part Version is 08S or Higher: If the installed door lock has part version 08S or higher, the technician should proceed with the diagnostic steps outlined for vehicles without an event memory entry, as described below.
3. If Part Version is 07S or Lower: If the part version is 07S or lower, a resistance measurement is required. The technician will use a multimeter to measure the resistance between pin 2 and pin 4 on the installed door lock. To ensure accurate measurement, the lock must be placed into temporary crash redundancy (TCR) mode. This is achieved by first removing the connector from the lock, then firmly pulling the interior door handle twice.
   • Expected Resistance Values:
     • Temporary crash redundancy (TCR) (without operating door handles): 1000 ohms
     • Switch for interior door handle (IDH) + TCR (operating interior door handle only): 382 ohms
     • Switch for exterior door handle (EDH) + TCR (operating exterior door handle only): 212 ohms (for vehicles with curved door handles, such as the Q5 type GU)
     • IDH + EDH + TCR (operating interior and exterior door handles simultaneously): 158 ohms (for vehicles with curved door handles)
   • A measurement tolerance of +/- 1% is acceptable for all values. After the initial measurement, the door should be closed, opened again, and the measurement repeated. At this point, instead of 1000 ohms for TCR, an