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2018 Audi Q5 Battery Drain & Start-Stop Malfunction - MMI Glitches Too!

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Jason D. · rep 0 · May 22, 4:28 AM · 1 replies · solved · Question

Vehicle: 2018 Audi Q5 Premium Plus

Hey everyone,

I've been having a really frustrating issue with my 2018 Audi Q5 Premium Plus. Over the last few weeks, the battery seems to be draining overnight, and I've had to jump-start it a couple of times. The start-stop system also stopped working entirely, and I'm getting a 'Start/Stop System Malfunction' message on the dash.

To make things worse, the MMI system has been acting up. Sometimes it freezes, or the screen goes black for a few seconds before restarting. I've checked the battery terminals, and they seem clean and tight. Could this be a bad battery, or something more complex like a module issue? I'm worried about getting stranded.

Any ideas on what could be causing this? I'm hoping to get some insight before taking it to the dealer.

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 22, 4:28 AM

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ClearTheCode admin answer:

It sounds like you're dealing with a classic case of an electrical system issue, potentially stemming from a failing battery or a parasitic draw. The MMI glitches and start-stop malfunction are strong indicators.

Here's what could be happening and what you can do:

  1. Diagnose the Battery:
    • Check Battery Health: Even if it's charging, the battery might be weak or have a bad cell. Most auto parts stores offer free battery testing. A failing battery can cause voltage drops that affect sensitive electronics like the MMI and disable systems like start-stop.
    • Look for OBD Codes: A low system voltage can trigger codes like P0562 (System Voltage Low) or P0560 (System Voltage Malfunction). Use an OBD-II scanner to check for these.
  2. Investigate Parasitic Draw:
    • This occurs when a component continues to draw power even when the car is off. Common culprits in Audis can include faulty infotainment modules, comfort control modules, or even a stuck relay.
    • Diagnosing a parasitic draw usually requires a multimeter and patience, systematically pulling fuses to isolate the circuit.
  3. MMI System Reset:
    • Sometimes, MMI glitches can be resolved with a hard reset. Consult your owner's manual for the specific button combination for your Q5 (often involves pressing NAV/MAP, CAR, and the central MMI knob simultaneously). This is a temporary fix if the underlying power issue isn't resolved.
  4. Alternator Check:
    • While less likely if you're getting jump-started, a failing alternator could also lead to undercharging the battery. Have its output tested to ensure it's providing adequate voltage (typically 13.5-14.5V).

When to See a Shop:

If a new battery doesn't resolve the issue, or if you're uncomfortable performing electrical diagnostics, it's best to take your Q5 to an Audi specialist or dealership. They have advanced diagnostic tools (like ODIS) that can pinpoint parasitic draws, module faults, and accurately test the battery management system. Ignoring persistent battery drain can lead to further damage to electrical components.

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