Flashing gear indicators and limp mode can make a TCU replacement sound inevitable. With P1746, a useful first distinction is whether the controller is receiving the supply it needs or has an internal problem.
Ross-Tech lists P1746, 18154 and 005958 as a transmission-solenoid power-relay electrical malfunction in this VAG context. It identifies low voltage at J743 and internal controller concerns, and points to wiring and connector checks. The 02E DSG note specifically calls for checking voltage at the mechatronic controller. Read the P1746 reference.
What does the existing test report actually establish?
“Battery replaced” and “power supply verified at the controller during the fault” are different pieces of information. Keep both in the history, but do not assume the first proves the second. Ask the technician to include the test conditions with measured results.
Tell us whether the fault appeared after a flat battery, water ingress, connector work or a replacement unit. If it happens only intermittently, record when the gearbox warning appears and whether other electrical warnings arrive at the same time.
Keep the original unit and identification
Before ordering a used replacement, save the complete scan and both hardware and software identifiers. Agree whether the next step is further vehicle testing, assessment of the original unit or a confirmed replacement route. Posting a controller without the surrounding findings can leave an intermittent supply issue unexplained.
Contact AXION with the P1746 report. Garages can include their existing diagnostic findings through the trade support route. Suitability for postal work should be agreed before removal.
Reviewed September 2026. Use the complete manufacturer-specific fault description and vehicle repair information.