C1103 on Audi
ABS/Brake System Circuit Fault (manufacturer-specific)
C1103 on Audi vehicles indicates abs/brake system circuit fault (manufacturer-specific). Au7o has documented this code across 1 Audi model — most commonly on A8. This is a chassis code set by the ABS/brake control module, and its precise meaning is manufacturer-specific. On many vehicles it refers to a fault in an ABS-related circuit such as the hydraulic brake switch or a wheel-speed/control circuit, while some makes (for example certain Mercedes-Benz) assign it to a specific axle circuit. In general it indicates the ABS module found an electrical problem in a brake-system input or control circuit, which can disable anti-lock braking and stability features. Because braking-related faults affect safety, it should be diagnosed against the correct service information for the specific make. Typical repair costs on Audi range from $200 to $2,000, depending on the specific model and root cause.
Common Causes of C1103
- •Faulty hydraulic brake/pressure switch (on applicable makes)
- •Wheel-speed sensor or related circuit fault
- •Damaged, corroded, or open wiring/connectors
- •Poor grounds or low supply voltage to ABS module
- •Internal ABS/EBCM module failure
- •Manufacturer-specific axle/sensor circuit fault
C1103 on Audi by Model
Audi A8(1 issue)
- Adaptive Cruise Control Radar Sensor Failure2011-2025
The A8 adaptive cruise control radar sensor, located behind the front grille, is prone to miscalibration and outright failure. Environmental contamination (road spray, ice, debris) can cause false alerts or system shutdown. The sensor requires precise alignment and even minor front-end impacts or bumper removal for service can knock it out of calibration.
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View C1103 across all makes →Frequently Asked Questions
What does C1103 mean on Audi?▼
C1103 stands for "ABS/Brake System Circuit Fault (manufacturer-specific)." This is a chassis code set by the ABS/brake control module, and its precise meaning is manufacturer-specific. On many vehicles it refers to a fault in an ABS-related circuit such as the hydraulic brake switch or a wheel-speed/control circuit, while some makes (for example certain Mercedes-Benz) assign it to a specific axle circuit. In general it indicates the ABS module found an electrical problem in a brake-system input or control circuit, which can disable anti-lock braking and stability features. Because braking-related faults affect safety, it should be diagnosed against the correct service information for the specific make. On Audi specifically, this code is documented across 1 model.
What causes C1103 on Audi vehicles?▼
Common causes on Audi: Faulty hydraulic brake/pressure switch (on applicable makes), Wheel-speed sensor or related circuit fault, Damaged, corroded, or open wiring/connectors, Poor grounds or low supply voltage to ABS module, Internal ABS/EBCM module failure. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix C1103 on a Audi?▼
Repair costs on Audi range from $200 to $2,000, depending on the specific model and root cause.
Which Audi models have C1103 documented?▼
Au7o has documented C1103 on 1 Audi model: A8.