Power Steering Whine Noise - keywords EHPS

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

A technician may comment of a power steering whine type noise. The noise may be present at all times.

The Electric Hydraulic Power Steering (EHPS) system uses hydraulic oil pressure produced by an electric hydraulic pump. The steering pump will only run when the engine is running to prevent the battery from discharging. There is a potential for a vacuum hose to transfer noise from the power steering line to the dash panel if the hose contacts the steering pump's high pressure line. The brake booster supplemental vacuum pump is located near the power steering pump/reservoir. A hard plastic hose leading from the vacuum pump to the booster may contact the high pressure line from the power steering pump causing a whine noise to be heard inside the cabin. (See illustration 1 for old retention with 2 clips) Beginning with chassis W08AR671685045589 a different design clip is used to prevent this condition from occurring. If this clip is not securing the hose properly or became loose a whine noise may be heard in the cabin area. (See illustration 2 for the new single clip and mounting location). Please insure that this vacuum line is not contacting the power steering lines.

Illustration 1

Illustration 2

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.