A distance of about 9500km, equipped with 7-speed dual-clutch automatic transmission (referred to as D7UF1) of the 2016 Beijing modern ninth generation Sonata (model referred to as LFc). Owners reflect: the car in the X431 scanner gear normal driving process, occasionally there will be a rapid continuous downshift, directly down to 1 block, sometimes normal.
Pick up the car after the Launch x431 test found that, as the owner said, the car in the D range normal driving process, the occasional rapid continuous downshift, directly down to 1 block. Due to continuous down gear transmission ratio is very large change, the vehicle slowdown, and a serious impact of the slowdown. Continue to travel, Launch X431 V Plus sometimes whether it is automatic mode, or manual mode shift, no any upshift trend; sometimes through the manual mode rose to 2 block, but quickly down to 1 block; sometimes normal; R gear normal.
With xtool x100 pro GDS modern special diagnostic machine scanning launch vehicle system fault code and transmission system data flow, the results shown in Figure 1, Figure 2, Figure 3, a historical fault code, but the normal flow of data. Replace the transmission board, the gear actuator, the clutch actuator, the gear switch, the gear lever TGS sensor, the dashboard, the junction box, and check the relevant line at the other repair shop.