What does it mean when an Audi reports terminal 30 power supply voltage for the steering angle sensor?

[MacBeau]

Audi reporting terminal 30 power supply voltage for the steering angle sensor is caused by low voltage. Audi is a German automobile brand, currently a subsidiary of Volkswagen Group. Its main models include A1, A3, A4, A5, A6, A7, A8, Q1, Q2, Q3, Q5, Q7, and Q8. Taking the 2020 Audi A6L as an example, its front suspension is a five-link independent suspension, and the rear suspension is also a five-link independent suspension. It is equipped with a 2.0T turbocharged engine with a maximum horsepower of 190PS, maximum power of 140kW, maximum torque of 320Nm, matched with a 7-speed dual-clutch transmission.

[StJosie]

Speaking of the power supply voltage fault code for the steering angle terminal 30, I encountered this issue before with my old A6L. After starting the car, the steering wheel suddenly became extremely heavy, and this warning popped up on the dashboard. You can't take such problems lightly, so I drove straight to a repair shop I trust. The mechanic checked and found poor contact in the constant power supply line of the steering gear module. Upon opening it up, the wiring harness connector was oxidized. He mentioned that Audi's electronic steering relies heavily on stable voltage, and especially when going over speed bumps, loose connections can trigger false fault reports. In the end, he re-crimped the connector and also polished the battery terminals—took two hours to fix. It would be really troublesome if this happened in rainy weather; the intermittent power steering would be particularly dangerous.

[Iris]

After inspecting several Audi vehicles reporting this fault, about 80% of the cases are due to electrical circuit issues. Terminal 30 refers to the main power supply line of the steering system, and abnormal voltage is mostly caused by aging wiring or poor fuse contact. Use a multimeter to measure the voltage at the steering gear's power connector—if it's below 12V, you can basically pinpoint the faulty area. Pay special attention to the SB10 fuse in the left fuse box in the engine compartment; this 20A fuse is dedicated to the steering module. Also, check the connector of the gateway control unit on the right side of the trunk, as water ingress there can easily lead to wiring corrosion. Don't forget to read the real-time data stream of the steering angle sensor; if the voltage fluctuation exceeds 0.5V, you'll need to inspect the alternator.

[SanCody]

This fault will directly affect the power steering! Terminal 30 is the constant power line, and the steering wheel may suddenly become heavy when the power supply is unstable. Last month, I helped a neighbor deal with a similar issue on their Q5 and found that the wiring harness under the steering column had its insulation crushed by the floor mat. Simply put, the troubleshooting can be divided into three steps: first, check if the battery voltage is normal; then inspect the steering module fuse in the engine compartment fuse box; finally, focus on examining the wiring harness connector of the steering gear. Pay special attention to 4WD models, as the chassis wiring is prone to water splashing and oxidation. When I handled it, I directly sprayed the connector with circuit protector, rewrapped the wiring harness, and the fault never recurred. Safety is no small matter—get it checked immediately.