A pulsating knocking noise (e.g. clattering) can be heard underneath the bench seat, particularly in the...

Bulletin number

LI47.10-P-079166

Component

Fuel/propulsion system

Summary

Complaint A pulsating knocking noise (e.g. clattering) can be heard underneath the bench seat, particularly in the case of a full tank (1/1 fill level). Cause The vibrating air column of the purge flow volume triggers the fill limit vent valve (FLVV) to open and close repeatedly when the fuel tank is full. Remedy By reducing the fuel quantity by around 5 liters, the noise can no longer be heard. In isolated cases, the noise can also be amplified by a fuel tank installed under stress and therefore lines adjacent to the body-in-white (above the fuel tank). In this case, the installation position of the fuel tank and the contact surfaces to the body-in-white must be checked. To do so, loosen the fuel tank and refasten it. Please do not replace component parts such as the fuel tank, activated charcoal canister, purge valve or delivery module, as this does not provide a remedy. If a similar noise can be heard with a tank fill level of, for example, 3/4 or 1/4 and not with a full tank (1/1), there is a different issue.

Owners of these vehicles have filed 26 complaints in the fuel system category.