By ALLDATA Tech-Assist Team
Here’s a compilation of some of the “Tech Tips” ALLDATA compiles as its Tech-Assist Team helps technicians tackle vehicle issues. More detail on these tips — including marked-up schematics, images and recommendations — are searchable in the “ALLDATA Community” (https://www.alldata.com/alldata-community).
VW Passat dual clutch transmission not shifting after fluid change
Problem: A 2018 Volkswagen Passat sedan (A33, V6-3.6L (CDVB), automatically-shifted manual transmission/transaxle with 162,556 miles was in the shop for a routine transmission fluid drain and fill. After the fluid change, the transmission would not shift on its own in “Auto” mode, and the malfunction indicator light (MIL) was illuminated in the instrument cluster.
Details: The technician retrieved the diagnostic trouble code (DTC) P1814 — Transmission Oil Pressure Control Valve 1, Open or Short to Ground. The DTC was not present when the vehicle came in for service. An ALLDATA Tech-Assist consultant advised that, after a transmission fluid change, it’s important to drive the vehicle through all the gears in “manual” mode for 30 to 45 minutes. Afterward, clear the DTCs, then put the transaxle in “Auto” mode it should operate normally. The pressure control valves must be primed or purged of air after a transmission fluid drain and refill.
Confirmed Repair: The technician drove the Passat with the transmission in “manual” mode as suggested. After driving for 45 minutes, he cleared DTCs and put the transmission in “Auto” mode. It operated as designed and the MIL stayed off.
Lexus IS 250 MIL on intermittently sets DTCs
Problem: A 2012 Lexus IS 250 (RWD, V6-2.5L, automatic transmission/transaxle with 139,007 miles was running well, but the MIL would occasionally come on. If the diagnostic trouble codes (DTCs) were cleared, after a few days, the MIL would come back on. The problem started happening …
