2021-2025 Audi Door Lock Malfunction TSB 2079747/1

Owners of 2021-2025 Audi vehicles may experience issues with their front or rear door locks, including doors that cannot be opened from either the outside or the inside. These issues are often accompanied by messages related to the door system, such as a "central locking system malfunction indicator" displayed on the instrument cluster. While the vehicle may still be locked, it might be possible to open a door without using a key.

This Technical Service Bulletin (TSB) 2079747/1 from Audi provides comprehensive guidance for technicians to diagnose and resolve these door lock complaints, ensuring proper functionality and addressing the root cause of the Audi door lock malfunction.

Symptoms of an Audi Door Lock Malfunction

The primary symptom reported by owners is that "Front or rear door cannot be opened from the outside or the inside." This can be a significant inconvenience and a safety concern. Additionally, drivers might observe "Messages related to the front or rear doors (e.g. regarding the exit warning system or central locking system) are displayed." The vehicle might be locked, but it is still possible to open a door without using a key.

Workshop findings confirm that the "Door locks do not work" as expected. These complaints indicate a problem with the door lock mechanism or its control system, leading to a general Audi door lock malfunction.

Diagnostic Trouble Codes (DTCs)

When an Audi door lock malfunction occurs, specific Diagnostic Trouble Codes (DTCs) may be logged in the vehicle's event memory. These codes help technicians pinpoint the exact nature of the problem. The TSB lists the following DTCs:

Diagnostic Address	Diagnostic Trouble Code	Fault Symptom	Storage State
0042 - Driver's door electronics	B122B13	Central locking motors Open circuit	static
0042 - Driver's door electronics	B14FF29	Motor for child safety lock implausible signal	intermittent
0042 - Driver's door electronics	B122D29	Lock unit for central locking implausible signal	static
00BC - Rear passenger side door electronics	B122D29	Lock unit for central locking implausible signal	static
0042 - Driver's door electronics	B122B13	Central locking motors Open circuit	intermittent
00BB - Rear drivers side door electronics	B14FF29	Motor for child safety lock implausible signal	intermittent
00BC - Rear passenger side door electronics	B14FF29	Motor for child safety lock implausible signal	intermittent
0052 - Passenger's door electronics	B122D29	Lock unit for central locking implausible signal	intermittent
00BC - Rear passenger side door electronics	B122D29	Lock unit for central locking implausible signal	intermittent
0042 - Driver's door electronics	B122D29	Lock unit for central locking implausible signal	intermittent
00BB - Rear drivers side door electronics	B122D29	Lock unit for central locking implausible signal	static
0052 - Passenger's door electronics	B122B13	Central locking motors Open circuit	static
0052 - Passenger's door electronics	B122B13	Central locking motors Open circuit	intermittent
0052 - Passenger's door electronics	B122D29	Lock unit for central locking implausible signal	static
00BB - Rear drivers side door electronics	B14FF29	Motor for child safety lock implausible signal	static
00BB - Rear drivers side door electronics	B122D29	Lock unit for central locking implausible signal	intermittent
0042 - Driver's door electronics	B14FF29	Motor for child safety lock implausible signal	static
00BC - Rear passenger side door electronics	B14FF29	Motor for child safety lock implausible signal	static

These DTCs indicate issues ranging from open circuits in the central locking motors to implausible signals from the child safety lock motor or the main lock unit. The storage state can be either static (persistent) or intermittent.

Understanding the Door Lock System

Audi's door lock system is sophisticated, relying on a combination of electronic and mechanical components. When a door handle (interior or exterior) is used, the action is transmitted electrically to the door control unit via a microswitch. This microswitch then activates an electric motor within the door lock; this motor releases the rotary latch and thus opens the door lock. This means that the door can be opened with very little effort.

For mechanical backup, two Bowden cables are still fitted, providing a mechanical connection between the door lock and the interior/exterior door handle (applicable to vehicles with mechanical exterior door handles). To open the door via this mechanical connection (e.g., in the event of messages or manual release if a microswitch or control motor fails), the interior door handle must be pulled out much further than the normal angle, specifically twice. In the event of a complaint, it is only possible to open the door using the exterior handle after the lock cylinder or the interior handle has been activated.

Audi notes that the door lock manufacturing process has been optimized.

Important Warnings and Owner Information

Audi emphasizes that some perceived door lock issues might stem from incorrect operation rather than a component failure. Before any repairs, technicians are advised to clarify the complaint with the customer and explain the door lock's operating concept, potentially referencing the Owner's Manual.

Owners of vehicles equipped with a mechanical exterior door handle and convenience key (sensor on the door handle, as shown in Figure 1) should be aware of specific operational nuances to prevent incorrect operation:

• When locking the vehicle: To lock the vehicle, close the door and touch the sensor on the door handle once. "Do not take hold of the door handle when doing so, otherwise the vehicle will not be locked." Once the doors have been locked, they cannot be opened immediately. This allows checking that the doors are properly closed.
• When opening the doors: "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), as otherwise the vehicle will be locked again -> incorrect operation by the user."

Figure 1 in the TSB illustrates the touch sensor on the mechanical exterior door handle.

Furthermore, regarding warranty claims, Audi states: "Replacing parts or attempting repairs without taking this TSB into account will not fix the problem. Unjustified work/replacement parts will be charged back. In this case, invoicing under warranty is not permitted." This underscores the importance of proper diagnosis according to TSB 2079747/1. An SoST film on the subject of the operating concept / incorrect operation / messages is available for reference.

Diagnosis and Repair Procedure Summary

Addressing an Audi door lock malfunction involves a systematic diagnostic and repair process:

1. Door Lock Function and Operating Concept

Technicians should first determine if the complaint is due to incorrect operation. This involves clarifying the details with the customer to narrow down the cause. The event memory entries listed can also occur with specific usage profiles:

• Is the interior door handle pulled too quickly or pulled past the end stop? This can result in messages or faults without there being a problem with the door lock.
• Does the door open if you pull the interior handle twice? Does the door then open again if the exterior handle is used? If so, there is no fault in the door lock.

Technicians should also consult the Owner's Manual, Workshop Manual, and Guided Fault Finding (GFF) for corresponding information.

2. Check and Diagnosis of the Door Lock

For every complaint, technicians must read out the event memory in the control unit and erase entries as appropriate. They should then check whether any event memory entries for the affected door are still logged. After erasing, switch the ignition off and on again, open and close the door, and then re-check the event memory. If entries persist, or if the door cannot be opened/closed in the usual way, proceed to "Resistance measurement at door lock."

Resistance Measurement at Door Lock

This procedure involves measuring the resistance on the installed door lock between pin 2 and pin 4 using a multimeter. To do this, the lock must be in temporary crash redundancy mode. This mode is initiated by removing the connector from the lock and firmly pulling the interior door handle twice.

Figure 2 in the TSB illustrates the connector for the door lock, showing the pin locations. Part 1 shows the connector for the right door lock, and Part 2 shows the connector for the left door lock.

Expected acceptable resistance values are:

• Temporary crash redundancy (TCR) (without operating door handles): 1000 ohms. If the value is not 1000 ohms, the interior door handle should be pulled twice again as far as the stop, and the measurement repeated.
• Switch for interior door handle (IDH) + TCR (operating interior door handle only): 382 ohms.
• For vehicles with curved door handles (e.g., Q6 e-tron and Q5 type GU) only:
  • Switch for exterior door handle (EDH) + TCR (operating exterior door handle only): 212 ohms.
  • IDH + EDH + TCR (operating interior and exterior door handles simultaneously): 158 ohms.

All measurements have a tolerance of +/- 1%. After the initial measurement, technicians should close the door, open it again, and repeat the measurement. Instead of 1000 ohms for TCR, an OL (open load) should now be measured.

If the results differ from the expected values and are outside the measurement tolerance range, the affected door lock should be replaced. If the results correspond to the expected values, the lock wiring should be checked according to Guided Fault Finding and the current flow diagram, then proceed to point 3.

3. Mechanical Check of Components

This step involves checking the mechanical Bowden cables at the door lock and at the interior/exterior door handle for any damage or irregularities (e.g., twisting, incorrect routing, traces of water or ice, stiffness). Technicians should compare the length of the Bowden cable to another vehicle if necessary and replace the affected component if needed. The door setting should also be checked for ease of movement and correct closing, and adjusted if necessary.

Important Note: "Only perform the following check for vehicle models listed in TSB 2060196:" Technicians must also check whether the exterior door handle returns to its flush original position (rest position) after it is operated. If it does not, they should modify or replace the door handle according to TSB 2060196, titled "57 Exterior door handles do not return to the zero position."

Warranty Information

For vehicles still under warranty, repairs related to this Audi door lock malfunction should be covered. The Claim Type for this TSB is informational only if the vehicle is outside of any warranty. The Damage Code associated with these repairs is 0040. Various labor operations are specified, each with a service number and estimated labor units (TU):

Labor Operations	Service Number	Time Units (TU)
Check 1-4 door handles	5711 0199	10 TU
Remove and install front door trim	7059 1900	See SRT with associated operations
Remove and install 2 front door trims	7059 2000	See SRT with associated operations
Check 1 front Bowden cable and wiring	5719 0199	10 TU + 7059 1900
Check 2 front Bowden cables and wiring	5719 0299	20 TU + 7059 2000
Measure 1 front door lock	5717 0399	5 TU + 7059 1900
Measure 2 front door locks	5717 0499	10 TU + 7059 2000
Remove and install front door lock	5717 19xx	See SRT with associated operations
Remove and install 2 front door locks	5717 2099	50 TU + 7059 2000
Q8 e-tron, e-tron: Remove and install 2 front door locks	5717 2099	120 TU + 7059 2000
A7: Remove and install 2 front door locks	5717 2099	170 TU + 7059 2000
Remove and install rear door trim	7073 1900	See SRT with associated operations
Remove and install 2 rear door trims	7073 2000	See SRT with associated operations
Check 1 rear Bowden cable and wiring	5819 0199	10 TU + 7073 1900
Check 2 rear Bowden cables and wiring	5819 0299	20 TU + 7073 2000
Measure 1 rear door lock	5817 0399	5 TU + 7073 1900
Measure 2 rear door locks	5817 0499	10 TU + 7073 2000
Remove and install rear door lock	5817 19xx	See SRT with associated operations
Remove and install 2 rear door locks	5817 2099	50 TU + 7073 2000
Charge battery	2706 8950	See SRT with associated operations
GFF / Guided Functions	0150 0060	Labor according to the diagnostic log

All warranty claims must adhere to the Audi Warranty Policies and Procedures Manual and are subject to review or audit by Audi Warranty. Claims submitted for work not performed according to this TSB, or for unjustified parts replacement, may be charged back.

---

NHTSA ID: 11025358