2016 Audi S8 Problems: 7 Known Issues

How to Fix

Check the VIN for open recall 20BM and contact an Audi dealer without delay. The free remedy installs a fuel-pressure damper in the low-pressure fuel supply inside the tank. If fuel odor or visible leakage is present, avoid ignition sources, do not continue driving, and arrange dealer inspection/towing as appropriate.

Owner tips & cautions

• WarningIf fuel odor or leakage is present, avoid ignition sources and arrange prompt dealer inspection; verify recall 20BM by VIN.

How to Fix

Check the VIN for open recall 21H7 and schedule the free Audi dealer remedy, which replaces the oil strainer and performs an oil change. If EPC, MIL or oil warning lights appear with unusual turbo noise, extended cranking, rough idle, loss of power or stalling, stop safely and arrange diagnosis. Turbo damage, warranty eligibility and any additional repair must be assessed by VIN and inspection.

Owner tips & cautions

• WarningVerify recall 21H7 by VIN. If the engine loses power or stalls, move to a safe location and arrange dealer diagnosis rather than repeatedly restarting.

How to Fix

Check first: have the level-control module (address 34) scanned with a VAG-capable tool, because a generic OBD2 scan misses these chassis codes. Audi lists codes for a system leak, compressor over-temperature and the level-control valves, which point to where to look. Then do a leak test: with the system pressurized, spray soapy water on each strut bellows, the upper mount area, the valve-block fittings and the nylon air lines. If one corner drops overnight, suspect a cracked strut bladder or a leaking valve-block solenoid. If the compressor runs for a long time and the car does not rise, the compressor is failing or a leak is too large for it. A slow strut leak will wear out the compressor, so find the leak before fitting a new compressor. Bulletin: Audi TSB 43 13 14 (2018765/8, "Self-leveling compressor inoperative") covers the 2011-2013 A8 (D4) with air suspension. The S8 is built on the D4 platform but is not listed by name. The technician tests the compressor on direct current and opens compressor relay J403. If the relay contacts are badly eroded or the strand is overheated, Audi says to replace both the compressor and the relay, even if the compressor sounds normal. If the contacts show only minor marks and the compressor sounds normal, replace only the relay. Coverage: no recall or warranty extension was found. Audi's bulletin says it is informational only once the car is out of warranty. Repair: replace the leaking strut. Aftermarket units cost less than new Audi struts. For example, the remanufactured Arnott AS-2865 front strut is listed for the 2013-2018 S8, but only for cars with sport suspension, so check fitment first. As a guide, a parts retailer's repair guide quotes $300-$600 per OEM strut plus $150-$300 labor per corner, $400-$900 for a compressor plus 1-2 hours of labor, and $3,500-$6,000 or more for a full system at a dealer on an A8 or Q7. An S8 buyer's guide puts a strut replacement at $1,000-$2,000 and a compressor at over $1,500, with dealers charging more.

How to Fix

1) Read the transmission fault memory first. If a 2013 S8 has P074100 stored and a warning light that clears after a restart, ask an Audi dealer about TSB 2028985/10. The fix is a TCM software update, then clearing adaptations and doing a standstill adaptation. It only applies if the ATF level is correct and there are no leaks. Outside any warranty, Audi treats this bulletin as informational only, so the owner pays. 2) If shifts feel rough on a 2013 S8 4.0 TFSI in VIN range 004908-013096, ask the dealer whether Update 37H1 (ECM and TCM software) is open for your VIN in ElsaWeb. Audi paid for 37H1 only when it showed as open for the VIN and the car was within the Federal Emissions Warranty. Otherwise the owner can choose to pay for it. 3) Check the ATF level and condition and look for leaks. For shudder, the first and cheapest step is a fluid change with the specified ATF, plus the filter where it can be serviced. 4) Only if shudder continues after the software, adaptation and fluid steps should a shop confirm converter-clutch slip and quote a new converter. That job means removing the transmission, so labor costs are high. Get a written diagnosis before you agree to replace the converter or valve body.

How to Fix

Have the dealer read DTCs and ODIS fuel-in-oil value, verify ECM software and perform Audi’s high- and low-pressure holding tests. If high-pressure behavior is abnormal, borescope the combustion chamber to identify a leaking injector. If low-side pressure builds correctly but drops more than 1.5 bar in the first 15 minutes, Audi says at least one HPFP may be leaking and directs replacement of both pumps plus an oil change. Don't replace a pump or injector until the tests show which one is leaking.

Owner tips & cautions

• TipRecord engine temperature and how long the car sat before the hard start; do not approve pumps or injectors without the pressure-hold results.

How to Fix

Clear and flush all sunroof and plenum/cowl drains; replace cracked drain hoses, grommets, or channel connectors. Dry out saturated carpet/insulation and inspect plenum-area modules for corrosion, replacing any water-damaged control units. Preventively clean the drains at least annually and keep the cowl area free of leaves/debris.

How to Fix

Compare the sound with Audi’s reference condition and check whether opening the oil filler cap changes it. Read P2279/P0507 and rule out other intake leaks. When the sound matches and is affected by the filler-cap check, follow Audi’s oil-separator breather replacement procedure and renew required seals/consumables by VIN. Do not diagnose by oil-cap feel alone.