Audi A6 Transmission Slipping and Hesitating Between Gears

Had similar issues with my 2004 Audi A4 2.0T. The symptoms turned out to be connected to a failing ABS control module affecting the transmission signals. The torque converter was getting incorrect input, causing those rough shifts and hesitation. Initially thought it was just transmission issues, but diagnostic trouble codes only showed up after the problem got worse. The vehicle eventually went into limp mode, limiting gear selection and speed. The repair needed multiple components checked since one fault led to another. The ABS control module required replacement, and the transmission needed recalibration to restore proper communication between systems. The transfer case also needed inspection due to the strain from improper shifting patterns. This was definitely a serious issue that required immediate attention. Continuing to drive with these symptoms risks damaging more components in both the transmission and ABS systems. The interconnected nature of modern vehicle electronics means one failing system can trigger problems in others. Would recommend getting it checked by a qualified technician who can perform a complete diagnostic scan, even without visible error codes.

Thanks for sharing your experience. Your situation sounds nearly identical to what I faced with my A6. The traction control warning light eventually came on after those initial transmission symptoms. I wonder if you could share what the total repair cost was in your case? Since fixing mine several months ago, I have had zero issues with gear shifts or the gear selector, but curious if you encountered any other related problems afterwards.

After getting the complete diagnostic scan at the shop, they traced everything back to the ABS control module like I suspected. The mechanic confirmed that once fixed, it resolved all the powertrain malfunction symptoms and the transfer case limp mode issue. The repair was actually covered under an extended warranty campaign for the ABS control module, so my total cost was 0 Euro. The transmission recalibration and consequential faults were all considered part of the same repair. Since the fix, the transmission has been shifting perfectly and no warning lights have returned. The diagnostic trouble codes haven't reappeared either. Just make sure to get any future transmission-related symptoms checked promptly, as catching these interconnected system issues early can prevent more extensive damage.

Thanks for the advice. I took my A6 to a certified transmission specialist last week. The diagnosis confirmed a faulty control module that was causing the transmission problems. The repair cost came to 850 Euro including parts and labor. They had to replace the control module and recalibrate the transmission to get everything working properly again. The mechanic also checked the transfer case but found it was undamaged despite the rough shifting. The car is now shifting smoothly again and no longer goes into limp mode. Been driving it for about a week with zero issues. The gear selector responds normally and all warning lights have cleared. Definitely worth getting it fixed before more damage occurred. Really glad I didn't wait longer, as the mechanic mentioned these problems tend to cascade and affect multiple systems if left unchecked. The torque converter was already showing early signs of strain from the improper shifting patterns.