Audi A6: Judder, slipping and control unit failure (01J Multitronic (A6 C5))
Judder, slipping and control unit failure (01J Multitronic (A6 C5)) is a common transmission fault on the Audi A6 on the 2000–2004 cars, and we rate it critical. Putting it right costs $1,200 to $7,000 at New Zealand independent workshop rates. Below is what goes wrong, the symptoms to notice on a test drive, where to look, and what to ask the seller before you hand over any money. It is one of 34 documented faults on the Audi A6.
- Vehicle
- Audi A6
- Years
- 2000–2004
- Gearbox
- cvt
- System
- Transmission
What you are looking at
No photograph available
What goes wrong
Front-wheel-drive C5 A6s from 2000 could be ordered with the 01J Multitronic CVT, which uses a steel link chain between two variable pulleys and a wet multi-plate clutch pack to pull away. The early 6-plate clutch pack judders and wears, and the transmission control unit bolted inside the gearbox fails from heat and oil seepage, giving a flashing gear display, jerky take-off and loss of drive. Audi later moved to a 7-plate clutch pack with new software, but there was no lasting extended warranty in NZ/AU and any goodwill is long gone. A control unit repair is moderate, but a worn chain or pulleys usually means a used or reconditioned gearbox.
What you would notice
- Shudder or judder when pulling away or creeping in traffic
- Gear indicator letters (PRNDS) flashing on the dash
- Jerk or thump when coming to a stop
- Revs flare without the car speeding up
- Reverse will not engage or car goes into limp mode
How to check it
Where to look. Gearbox between the engine and the front wheels; control unit is mounted inside the gearbox
Check the dash gear display is steady and not flashing at any point during the drive. From a stop, pull away gently on a slight uphill and in slow traffic-style creeping: any shudder, vibration or grabbing is the classic early warning. Accelerate firmly from 50 km/h and watch the rev counter: revs should rise smoothly with road speed, not flare. Come to a full stop several times and feel for a clunk or jerk just before stopping. Select reverse and drive a few metres. Ask for invoices showing CVT fluid changes about every 60,000 km, clutch pack or control unit work, and any software updates. If a workshop inspection is possible: read the gearbox control unit fault codes and clutch adaptation values with a scan tool, and check the fluid condition.
What it costs to put right
$1,200 to $7,000 at New Zealand independent workshop rates. That is for this job on its own, not for the car.
Ask the seller
- “Has the CVT fluid ever been changed, and when?”
- “Has the gearbox control unit or clutch pack been replaced or repaired?”
- “Has the gear display ever flashed on the dash?”
- “Has the gearbox software been updated?”
Now check the Audi A6 you are actually looking at
Everything above is true of the model, and it is free. What it does not tell you is whether THIS car has been looked after: its odometer history and whether the reading has ever gone backwards, whether there is still money owing on it, whether it has been reported stolen, how many owners it has had and what it is really worth today. That comes from the official records for that plate. Enter the plate for the free details, or get the full history and a market valuation from $13.49.
Where this comes from
- Wikipedia: Multitronic (01J/0AN TCU and clutch pack problems)
- ECU Testing: Audi A4 A6 Multitronic auto transmission ECU common fault
- AudiForums.com: A6 Multitronic CVT judder
- Audi-Sport.net: multitronic problems
Audi A6 buyer questions
Is judder, slipping and control unit failure (01j multitronic (a6 c5)) serious on a Audi A6?
We rate it critical and common on the Audi A6. Front-wheel-drive C5 A6s from 2000 could be ordered with the 01J Multitronic CVT, which uses a steel link chain between two variable pulleys and a wet multi-plate clutch pack to pull away. The early 6-plate clutch pack judders and wears, and the transmission control unit bolted inside the gearbox fails from heat and oil seepage, giving a flashing gear display, jerky take-off and loss of drive. Audi later moved to a 7-plate clutch pack with new software, but there was no lasting extended warranty in NZ/AU and any goodwill is long gone. A control unit repair is moderate, but a worn chain or pulleys usually means a used or reconditioned gearbox.
How much does it cost to fix on a Audi A6?
$1,200 to $7,000 at New Zealand independent workshop rates. That figure is for this job on its own. A car showing the symptoms on this page is usually worth either walking away from or negotiating down by at least the repair figure.
Which Audi A6 years are affected?
Our research records this fault on the 2000–2004 Audi A6. Build dates move around, especially on imported cars, so treat the range as the years to look hardest at rather than a guarantee either way. The official records tell you the exact build and first registration date for the car in front of you.
How do I check for it before I buy?
Check the dash gear display is steady and not flashing at any point during the drive. From a stop, pull away gently on a slight uphill and in slow traffic-style creeping: any shudder, vibration or grabbing is the classic early warning. Accelerate firmly from 50 km/h and watch the rev counter: revs should rise smoothly with road speed, not flare. Come to a full stop several times and feel for a clunk or jerk just before stopping. Select reverse and drive a few metres. Ask for invoices showing CVT fluid changes about every 60,000 km, clutch pack or control unit work, and any software updates. If a workshop inspection is possible: read the gearbox control unit fault codes and clutch adaptation values with a scan tool, and check the fluid condition. Look here: Gearbox between the engine and the front wheels; control unit is mounted inside the gearbox