2004 Audi A4 Problems

What owners report

Owners of the 2004 A4 most often describe the car quitting or losing power while driving, with the fuel pump named repeatedly as the cause, and many note that the 2003 model was recalled for a similar pump but the 2004 was not. A second recurring theme is the airbag warning light staying on, plus oil sludging and cooling-system failures that owners say led to engine replacement. Complaints span a wide mileage range, from near-new cars to over 150,000 miles.

1. 1
   Fuel system

   Fuel pump failure causing stall or loss of power

   • 50 complaints (26%)
   • median 64,925 mi at 5.9 yrs old (50 state mileage)
   • 1 mention a crash, fire or injury
   • owner-quoted repair $750 (median of 11 quotes)
   • filed 2007–2020

   Complaints describe the engine cutting out without warning while driving, at highway speed or in traffic, sometimes followed by a restart after a wait and sometimes by a no-start. Dealers and independent shops commonly diagnosed a failed fuel pump and replaced it; several owners mention the repair cost plus towing, and some say a replacement pump later became noisy or failed again. Multiple owners point out that a similar pump was recalled on the 2003 model but not on their 2004. Most often reported between about 34,000 and 106,000 miles, with a few earlier and several past 100,000.

   5 related service bulletins

   What to check: Ask whether the fuel pump has been replaced and when, and have a pre-purchase inspection listen for a whining pump or check for stored fuel-system codes. Note that the 2003-model pump recall does not cover this year.

   2 excerpts from owner complaints in NHTSA records

   “I was driving on the highway and the car suddenly lost power without warning, due to fuel pump failure. I have seen a lot of complains about this defect. I think Audi should take responsibility for this safety issue. The Audi should recall the car to prevent this from happening to other Audi owners, because it is very dangerous to loss power on the highway without any warning.”

   NHTSA complaint #10427000, filed 2011-09, 89,000 miles

   “I was driving hwy speed limit while my Audi A4 3.0 2004 stopped running all of a sudden and I had to push my car on the side to safe from hwy traffic. I tried to restate the engine but I couldn't start. I found out my fuel pump stop working bc it was shaking and lost the power and shuts off by itself. …”

   NHTSA complaint #10372439, filed 2010-12, 105,000 miles
2. 2
   Air bags

   Airbag warning light on

   • 15 complaints (8%)
   • median 78,071 mi at 6.7 yrs old (12 state mileage)
   • 2 mention a crash, fire or injury
   • filed 2004–2018

   Owners describe the airbag warning lamp lighting and staying on, sometimes flashing intermittently, with no crash involved. In some complaints the dealer found water in the airbag connectors under the center console and cleaned the contacts; in others the dealer replaced an airbag or could not resolve the light. One complaint describes the passenger airbag deploying in a frontal impact while the driver-side bag did not. Reported from roughly 7,500 up to 100,000 miles, across a wide range of ages.

   Recall 16V3820003 related service bulletins

   What to check: Check that the airbag lamp comes on with the key and goes out, and ask whether the passenger-side inflator recall (16V382000) was completed. A scan for airbag module fault codes is worth doing.

   2 excerpts from owner complaints in NHTSA records

   “My husband and I own a 2004 Audi A4 cabrio and took it in for a voluntary emissions service action for an ignition coil replacement on feb 4, 2010. At that time, the dashboard light for the driver side airbag was on constantly and would not go off so we asked the service department to look into it. They told us we needed a new airbag and replaced it at a cost of $746.14. We had not been in a collision and had not tampered with the airbag either.”

   NHTSA complaint #10317800, filed 2010-03, 69,695 miles

   “The air bag light is on. The consumer had the air bag replaced and the dealer has serviced the vehicle several times, but the light continues to stay on.”

   NHTSA complaint #10105415, filed 2004-12, 7,500 miles
3. 3
   Engine cooling

   Oil sludge leading to engine damage

   • 8 complaints (4%)
   • median 98,500 mi at 6.8 yrs old (8 state mileage, few)
   • filed 2009–2015

   Complaints describe the low-oil light coming on and the engine later failing, with dealers and mechanics attributing it to sludge blocking lubrication passages, in some cases requiring engine replacement or rebuild. Several owners say warranty coverage for the sludge condition was denied because they lacked oil-change receipts, and others describe oil consumption or oil-pressure warnings before the failure. Typically reported between about 80,000 and 113,000 miles, though one case is near 99,000 and another at 38,000.

   3 related service bulletins

   What to check: Ask for a documented oil-change history and check the oil level and condition on a cold engine; an independent inspection can look for sludge under the filler cap and for oil-pressure warning history.

   2 excerpts from owner complaints in NHTSA records

   “One day the low oil light came on, brought it to carousol Audi in golden valley mn and they informed me about the oil sludge problem and told me to get my oil receipts ready. I changed my own oil and don't have my oil receipts and am now being denied a warranty coverage. Was told that I would have a new engine put in if I had oil receipts but will cost at least 9000 without the warranty.”

   NHTSA complaint #10349391, filed 2010-08, 80,000 miles

   “2004 Audi A4 1.8t engine sludge--complete engine failure. Audi absurdly refuses to honor their own extended warranty on the basis the car was run without oil. The engine failed internally because there was and is sludge blocking lubrication ports to the moving parts, I.e., failure. This is my executive synopsis, but I have volumes of supporting evidence, unbelievable as it is to think this could happen in america.”

   NHTSA complaint #10356718, filed 2010-09, 99,000 miles
4. 4
   Vehicle speed control

   Sudden unintended acceleration / stuck accelerator

   • 14 complaints (7%)
   • median 47,000 mi at 6.0 yrs old (13 state mileage)
   • 1 mention a crash, fire or injury
   • filed 2004–2016

   Owners describe the accelerator dropping to the floor or staying down on its own, with the car accelerating hard while braking was used to slow it. In several cases the pedal returned to normal after the engine was shut off and restarted, and dealers reported finding nothing on test drives. One complaint notes a bulletin about the car losing power when the brake and accelerator are pressed together. Mostly reported between about 11,500 and 90,000 miles, often during highway merging or passing.

   1 related service bulletin

   What to check: Ask whether the throttle pedal assembly or engine control software has been serviced, and check that floor mats are correctly secured; a scan for throttle-related fault codes is useful.

   2 excerpts from owner complaints in NHTSA records

   “I was driving my 2004 Audi A4 (1.8, convertible) on a local road at approx 30mph, when the accelerator suddenly dropped from under my foot and the car accelerated very rapidly. It felt like the cruise control had come on by itself (the cruise control was completely off at the time). I put the car in neutral and pulled over. When I shut the car off, the gas pedal popped up and felt normal. When I turned the car back on several times, it continued to immediately accelerate all the way with the gas pedal dropping to the floor. …”

   NHTSA complaint #10549744, filed 2013-10, 41,000 miles

   “On three separate occasions over the past 3 years, we have lost control of acceleration in our 2004 A4. I have pressed my accelerator to pass on a highway and the accelerator continues to go down increasing speed of car against my will....on first two occasions I was able to pump breaks and kick gas pedal for release (and assumed it was a mat issue, however I started to question that issue on the second occasion after inspection of my mat and I also felt like the pedal pressed away from my foot all its own, like on cruise control even thought …”

   NHTSA complaint #10455603, filed 2012-04, 74,000 miles

Summary written with AI from a sample of 60 NHTSA complaints for this model year (picked at random, with complaints that state a mileage and recent ones taken first), then checked automatically against the source records. Where a problem shows a complaint count, every complaint for this model year was matched with fixed keyword rules (written with AI and tested against the sample), and the mileage, age and repair figures are calculated from those complaints; owners' figures are as stated, not verified. Other counts refer to the sample. The excerpts come from NHTSA's public complaint records and are unverified; capitalisation is normalised, NHTSA staff notes are removed, and shortened text ends with “…”. Something wrong? Request a correction.