We would like to expressly state that the cause of the faults described here almost always lies outside the control unit.
Please always send your device to us after conducting a thorough troubleshooting process.
Error codes stored in the central electronics (BCM) of Volkswagen Group vehicles with the designation “Interruption terminal 30” relate to errors in the power supply at the input of the control unit. “Terminal 30” refers to all current paths in an on-board electrical system that are permanently supplied with positive potential.
- 03435 – Terminal 30 for interior light/parking light: 011 – Interruption – Sporadic
- 03430 – Terminal 30 for turn signals/brake lights: 011 – Interruption
- 00927 – Terminal 30 right: 011 – Interruption
- 01516 – Terminal 30 left: 011 – Interruption
- 02391 – Terminal 30 reference: 011 – Interruption
Further faults relating to the failed function are possible. These should be treated as consequential faults. The depth of diagnosis depends on the variant of the central electronics, the vehicle model and equipment, as well as the BCM manufacturer and software version.
Such faults are caused by permanent interruptions to the terminal 30 supply as a result of defective fuses or interruptions to the current paths/cables. Fuse defects are due to permanent overloading or short circuits of the cables against negative potential (ground).
Consequential errors often include failures of central electrical functions such as exterior lighting, windshield wipers, and turn signals.
In Volkswagen Group vehicles, the central electrical system is responsible for distributing power to the on-board electrical system, controlling the exterior lighting and windshield wiper/washer system, and controlling the signaling devices. The circuits are fused upstream of the central electrical system at the input. The voltage can also be switched by relays upstream of the control unit. This is referred to as “switched terminal 30.” The function of the on-board power management system requires internal load control of all directly connected components and the exchange of information via CAN with control units that control high-current consumers. The central electrical system thus simultaneously performs complex control tasks and diagnostic processes for the connected components and their functions.
All input variables and information as well as output signals pass through the diagnostic filter. The positive potential supply, terminal 30, and the ground potential supply, terminal 31, are connected to the ZE in multiple ways. This means that the computer, as well as the basic functions and diagnostics, are protected when the components and consumers are divided up logically.
Selective emergency operation is possible. Only the directly affected components and their functions fail. Since the inputs of terminal 30 are divided according to the left and right sides of the vehicle and according to functions in order to maintain functional safety for the exterior lighting, component groups fail according to this division.
Possible emergency operation strategy:
- Compensation for a lamp failure by means of replacement control (depending on the programming).
- Deactivation of the control of the current paths to avoid consequential damage. (Consequential errors possible)
The noticeable malfunction and failure of the components must be linked to the diagnostic code and checked first at the input of the power supply chain using the circuit diagram and the fuse assignment plan. Terminal 30 is only connected to the input of the central electrical system via fuses in the fuse and relay box in the engine compartment.
- Check the fuses on terminal 30.
- Check the cable for ground faults and under load.
- Check the fuse holder to ensure that the fuse is securely seated.
- Check the fuse holder for heat damage.
- Check the fuse holder for water damage and corrosion.
- Inspect the cable harness for improper modifications and retrofits.
If several faults are stored, the fault at terminal 30 must be dealt with first. In unclear situations, the primary fault is displayed by deleting all faults, resetting the ignition, and reading the faults again. It may be necessary to change the ignition several times before the fault is generated in the central electronics.
If all external sources of error have been ruled out after all of the above checks, we can offer you repairs for the following devices:
