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2003 Volkswagen Jetta P1635 P0733 P0734 Transmission Issues - Diagnosis and Solutions

Model: 2003 Volkswagen Jetta Fault Code: P0733 Posted: 2015-12-25 20:46

I own a 2003 Volkswagen Jetta V6 2.8L with persistent transmission error codes P1635, P0733, and P0734. The car has a Tiptronic transmission, and I'm only concerned about first and second gear performance—no need to overhaul the entire transmission. I've already checked the transmission fluid level, but it's not low. I'd like to understand what these codes mean and where to start troubleshooting without unnecessary repairs. Any guidance on diagnosing P1635 (related to AC system), P0733 (AT valve body solenoid issue), and P0734 (similar transmission control problem) would be greatly appreciated. Thanks in advance for any help.

Related fault codes
P0733P0734P1635
Comments (3)
Anonymous 2015-12-25 20:47

Common transmission-related issue in 2003 Volkswagen Jetta, especially with V6 models and Tiptronic systems.

Anonymous 2015-12-26 10:47

Have you recently changed tire or wheel sizes? If so, this could affect vehicle speed sensor (VSS) readings. Also check the VSS itself, its wiring harness, connectors, and grounding—these are common sources of P0733 and P0-734 errors.

Anonymous 2015-12-28 09:42

P1635 typically indicates a disturbance in AC system can lines or a faulty A/C control module—common in VW/Audi vehicles. A professional VW/Audi-certified technician should inspect this to confirm the root cause. P0733 and P0734 point to issues with transmission valve body solenoids. While full transmission replacement is often required, some users have reported success using valve body oil passage drilling—a technique found in certain forums. Search for 'valve body drilling 2003 Jetta' to find detailed guides or case studies from individuals in California. This method may offer a cost-effective alternative, but it's not guaranteed and should be approached with caution.