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2017 A6 3.0T MMI Glitches and Battery Drain

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Angela R. · rep 0 · May 22, 4:23 AM · 1 replies · solved · Question

Vehicle: 2017 Audi A6 3.0T Prestige

Hi everyone,

I'm having some weird electrical issues with my 2017 Audi A6 3.0T Prestige. For the past few weeks, the MMI system has been acting up – freezing, restarting randomly, and sometimes not turning on at all. It's really frustrating, especially when trying to use navigation or connect my phone.

To make matters worse, I've noticed a significant battery drain. If I leave the car parked for more than a day or two, the battery is completely dead. I've had to jump-start it multiple times. I suspect these issues might be related.

Could a faulty MMI module be causing the battery drain? Or is there something else I should be looking at? I haven't pulled any specific OBD-II codes related to this, but I'm wondering if there are hidden codes or common Audi issues that fit this description. Any advice on where to start troubleshooting would be great!

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 22, 4:23 AM

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ClearTheCode admin answer:

Your 2017 Audi A6's MMI glitches and battery drain are indeed likely related, pointing towards a parasitic draw, often caused by a module that isn't properly shutting down. While you might not see generic OBD-II codes, an Audi-specific scan tool (like VCDS or ODIS) would likely reveal fault codes within the MMI, Gateway, or Power Management modules.

Common Causes for MMI Glitches and Battery Drain:

  1. Faulty MMI Control Module: A failing MMI unit can stay 'awake' even when the car is off, continuously drawing power and draining the battery. It can also cause the system to freeze or restart.
  2. Component Protection Issues: After a module replacement or software update, sometimes component protection isn't properly activated, leading to module malfunctions and potential draws.
  3. Gateway Module Issues: The Gateway module manages communication between various control units. A fault here can prevent modules from entering sleep mode.
  4. Software Glitches: Outdated or corrupted MMI software can cause erratic behavior and prevent proper shutdown.
  5. Aftermarket Accessories: Any non-factory installed electronics (dash cams, radar detectors, etc.) that are not properly wired can cause parasitic draws.
  6. Other Failing Modules: Less commonly, other modules (e.g., comfort control module, telematics unit) can fail to go to sleep, causing a drain.

When to See a Shop:

Diagnosing parasitic draws and MMI issues requires specialized knowledge and tools. A professional Audi technician can perform a proper parasitic draw test and use an advanced scan tool to read all module fault codes and monitor module sleep states. This is crucial to avoid replacing parts unnecessarily.

Steps for Diagnosis:

  1. Full System Scan: A shop will perform a comprehensive scan of all control modules using an Audi-specific diagnostic tool. This will reveal any communication faults, power supply issues, or internal module failures that generic OBD-II scanners miss.
  2. Parasitic Draw Test: This involves connecting an ammeter in series with the battery and monitoring current draw over time. The technician will then systematically pull fuses to isolate the circuit causing the draw.
  3. MMI Software Update: Check if there are any available software updates for your MMI system. Sometimes, a simple update can resolve glitches.
  4. Module Reset/Re-adaptation: In some cases, a hard reset or re-adaptation of the MMI or related modules can resolve temporary glitches.
  5. Visual Inspection: Check for any signs of water intrusion in the trunk (where some MMI components are located) or under the seats, which could damage electronic modules.
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