Audi Network Map
Audi introduced CAN architecture to US-market vehicles around 2004 (model-year dependent). Early systems used multiple CAN buses managed by a central gateway module that brokers cross-bus communication. Architecture later expanded to include an infotainment CAN and chassis/ADAS buses. From approximately 2018 forward, most models adopted a security gateway requiring online authentication for most control-module programming, coding, adaptation, and some advanced diagnostics. Diagnostic access is primarily gateway-mediated; direct DLC access is typically limited to the powertrain/drivetrain CAN, while convenience and infotainment buses require the gateway.
Testing values and scope patterns are universal — they live on the main CAN playbook. This page is what's specific to Audi: the buses, where the terminators live, and what breaks. Tap any era to explore it — network map, testing guide, failure patterns.
2004-2008
Early CAN gateway architecture
Some early models still ran K-line for certain modules alongside CAN. Gateway is critical; failure kills scan access to comfort systems.
| Bus | Speed | Carries | DLC access | Terminators live in |
|---|
| Powertrain/Drivetrain CAN | 500 kb/s | Engine, transmission | DLC pins 6/14 | not independently confirmed |
| Convenience/Comfort CAN | 100 kb/s | Convenience modules, door control units, central electrics | via gateway only | not independently confirmed |
GatewayGateway control module (J533), location varies
Explore this era ⤢2009-2017
Expanded multi-CAN architecture
FlexRay present on some models for chassis systems. FlexRay not accessible via standard DLC.
| Bus | Speed | Carries | DLC access | Terminators live in |
|---|
| Powertrain/Drivetrain CAN | 500 kb/s | Engine, transmission | DLC pins 6/14 | not independently confirmed |
| Convenience/Comfort CAN | 100 kb/s | Convenience modules, door control units, central electronics, steering column electronics | via gateway only | not independently confirmed |
| Infotainment CAN | 100 kb/s | MMI/navigation, amplifier, telephone | via gateway only | not independently confirmed |
GatewayGateway (Data Bus Diagnostic Interface) J533, location varies
Explore this era ⤢2018-present
Security Gateway (SGW) era
Security Gateway (SGW) requires online VIN-linked authentication for most module programming, coding, adaptation, and some advanced diagnostics. Basic fault-code reading usually possible without auth. Ethernet backbone common for cameras and driver-assist.
| Bus | Speed | Carries | DLC access | Terminators live in |
|---|
| Powertrain/Drivetrain CAN | 500 kb/s | Engine, transmission, hybrid/electric drive components (if equipped) | DLC pins 6/14 | not independently confirmed |
| Chassis/Extended CAN | 500 kb/s | ABS/ESP, steering | via gateway only | not independently confirmed |
| Convenience/Comfort CAN | 100 kb/s | Convenience modules, door control units, seats, HVAC, lighting | via gateway only | not independently confirmed |
| Infotainment CAN | — | MMI, displays, amplifier | via gateway only | not independently confirmed |
GatewaySecurity Gateway / central gateway module (J533), location varies
Explore this era ⤢What breaks on Audis
Footwell water intrusion (sunroof drains / HVAC)
Clogged sunroof drains or HVAC drain cause water pooling in driver or passenger footwell, corroding gateway module and CAN wiring. Often accompanied by musty smell. Check carpet moisture and drain tube routing.
Aftermarket accessory / trailer module CAN conflicts
Aftermarket trailer modules, alarms, or remote starters tapped into CAN without proper isolation or coding cause bus faults, phantom warnings, or intermittent failures. Requires proper coding or isolation from powertrain CAN.
The bench — what to test with
Decent DVOM with a true 200-ohm manual range$40-150; cheap genuinely works here
Terminator resistance (~60 ohms), idle bias voltage (~2.5V), short-to-ground/short-to-power checks, and split-half short hunting are all just physics a plain meter reads fine — this catches the majority of real CAN faults, provided you honor bus sleep for resistance. Manual range beats autorange for stable low-ohm reads.
Two-channel automotive oscilloscope$200-600 for a usable 2-channel scope; USB scopes cheaper, standalone handhelds cost more
The scope is what shows you WHY a bus is unhealthy — reflections from a missing terminator, one flat line, error frames, a babbling node, or a bus that's alive behind the gateway but not reaching the DLC; a meter only averages the traffic away. Essential for intermittents and waveform faults.
Fine backprobe pin set / needle probes$15-40
Comfort, infotainment, and chassis buses never reach the DLC, so you must backprobe module and gateway connectors from the wire side without piercing insulation and creating tomorrow's corrosion — good probes make this repeatable and non-destructive.
VAG-compatible scan tool with online SGW authenticationEnthusiast VAG tools start a few hundred dollars; genuine online SGW authentication requires a manufacturer-portal-capable tool and subscription
Non-powertrain buses are gateway-mediated and, from 2018+, coding/adaptation/programming require VIN-linked online authentication; a generic OBD-II reader only reaches emissions data on the powertrain bus. The authentication capability, not the box price, is what matters on 2018+.
OBD-II / DLC breakout box$30-150; optional if you're comfortable probing the DLC directly
Lets you land clean leads on pins 6/14 (and verify 4/5/16 power and grounds) without stressing the connector, and gives a stable point for split-half isolation at the DLC; a convenience, not a requirement.
Scan-tool access
Pre-2004 models use K-line (ISO 9141 or KWP2000); CAN adoption begins around 2004 and is model-dependent. CAN on DLC pins 6/14 for the powertrain bus. VW/Audi-specific protocols required; generic OBD-II scanners often limited to emissions data. Full system access requires a VAG-compatible scan tool, with gateway access required for non-powertrain buses. From 2018+, secure gateway (SGW) vehicles require online VIN-linked authentication for module coding, adaptation, and programming; basic fault scanning usually works without auth, but advanced functions are locked.