Suspension - Underbody Knocking Noises

Date: May 13, 2009

Order No.: P-B-32.50/79

Supersedes:

Group: 32

SUBJECT:
All Model 216 Vehicles
All Model 221 Vehicles, Equipped with Active Body Control (sales code 487)

Knocking Noise from Under floor When Driving Over Bumps or When Stationary














If you receive customer reports in the above model vehicles of a knocking noise from the under floor area when driving over bumps or when stationary, inspect the ABC hydraulic lines for proper routing. If contact and/or tension is discovered, reposition and/or relieve the hydraulic line. It is imperative that the ABC hydraulic lines do not contact the body and must also be free of tension. Reference Figures 1 through 4 for contact area examples. ABC lines which make contact along various points of the body can introduce pressure pulsation noises into the passenger compartment when the suspension struts are activated.

Note:
The knocking noise can be heard in a vehicle speed range up to 30 mph when driving over slight unevenness and surface undulations. The noise may also be present when the vehicle is stationary with the engine running and the transmission in drive. When the vehicle is stationary, pulsations can be felt under the vehicle on the ABC pressure lines.

Note:
Suspension parts should not be replaced in these cases.

Note:
The following allowable labor operations should be used when submitting a warranty claim for this repair. This information has been generated on May 13, 2009. Please refer to Netstar --> Star TekInfo --> Star Time for the most current labor time allowance.





In Case of Warranty, use the table above.