Question: On May 21 last year, when I stopped my 2003 Audi A6 2.4 Multitronic at an intersection, I suddenly had no gears and the P-R- N-D display was flashing orange. The car was taken by low loader to a company considered to be the experts on Multitronic gearboxes. During the next six months, the car was with them for a total of at least five months, making the trip there and back at least 12 times. The control unit has been changed six times, and just about everything else in the gearbox at least once. When the car is returned, it will behave normally when cold. As soon as it warms up — after 30 to 50km—and I slow to a stop, the trouble starts. The dash lights flash, the car does not select a gear and will not rev. I took it to an Audi agent, and the computer diagnosis was “replace hydraulic control unit”. This was done, and it went for 20km before stopping again. I now have a vehicle in excellent condition that doesn’t run. Please help!
Answer: This is a veritable horror story, Roger. Audi’s Multitronic was a continuously variable transmission, under electronic control. The CVT mechanism had a good reputation for durability. But the electronic control unit is a different kettle of fish. I discussed your letter with a technician at a local transmission workshop with considerable experience in Multitronic problems. His reaction, after studying it in detail, was: “Everything in this report shouts control unit!” The circuit board for the control unit, he explained, has a multitude of fine wiring connectors coming into it. A dry joint, or an almost invisible break, on one of those connectors will produce symptoms like you describe. A new control unit is very expensive; the temptation is to try to repair the old one. The technician I spoke to has a firm policy: try to repair once, but if it malfunctions again, scrap it, bite the bullet and buy a new one. Otherwise you are throwing good money after bad. The question I ask myself is: throughout this saga, has a new control unit from the agents ever been installed?
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