Use the information gained from the customer to accurately begin the diagnostic process.
2: Pre-Drive Check
It is important to do a pre-drive check before road testing the vehicle. A pre-drive check verifies that the vehicle is safe to drive and eliminates any obvious faults on the vehicle.
The pre-drive check consists of a brief visual inspection. During this brief inspection, take note of anything that will compromise safety during the road test and make those repairs/adjustments before taking the vehicle on the road.
3: Preparing for the Road Test
Observe the following when preparing for the road test:
Review the information provided by the customer. It is important to know the specific concern the customer has with the vehicle. Do not be misled by the reported location of the noise/vibration. The cause can actually be some distance away. Remember that the vibrating source component (originator) may only generate a small vibration. This small vibration can in turn cause a larger vibration/noise to emanate from another receiving component (reactor) due to contact with other components (transfer path). Conduct the road test on a quiet street where it is safe to duplicate the vibration/noise. The ideal testing route is an open, low-traffic area where it is possible to operate the vehicle at the speed at which the condition occurs. If possible, lower the radio antenna in order to minimize turbulence. Identify anything that could potentially make noise or be a source of wind noise. Inspect the vehicle for add-on items that create vibration/noise. Turn off the radio and the heating and cooling system blower.
4: Verify the Customer Concern
Verify the customer concern by carrying out a road test.
A road test may be necessary if the symptom relates to the suspension system or is sensitive to torque.Remember, a condition will not always be identifiable by carrying out these tests; however, they will eliminate many possibilities if carried out correctly.
5: Road Test
NOTE: It may be necessary to have the customer ride along or drive the vehicle to point out the concern. During the road test, take into consideration the customer's driving habits and the driving conditions. The customer's concern just may be an acceptable operating condition for that vehicle.
The following is a brief overview of each test. A review of this information helps to quickly identify the most appropriate process necessary to make a successful diagnosis. After reviewing this information, select and carry out the appropriate test(s), proceeding to the next step of this process.
The Slow Acceleration Test is normally the first test to carry out when identifying an NVH concern, especially when a road test with the customer is not possible. The Heavy Acceleration Test helps to determine if the concern is torque-related. The Neutral Coast Down Speed Test helps to determine if the concern is vehicle speed-related. The Steering Input Test helps to determine how the wheel bearings and other suspension components contribute to a vehicle speed-related concern. The Brake Test helps to identify vibrations or noise that are brake related. The Road Test Over Bumps helps isolate a noise that occurs when driving over a rough or bumpy surface. To identify if the noise is coming from the electric motor and /or gearbox (such as for a whine issue), it can be helpful sometimes to shift into neutral while driving while the condition is present. The Vehicle Cold Soak Procedure helps to identify concerns occurring during initial start-up and when an extended time lapse occurs between vehicle usage.
2016 Mustang workshop publication supplied to Mustang Atlas. Original technical text and illustrations; HTML formatting by Mustang Atlas. Source page numbering is retained for traceability. Follow the configuration, revision, warnings, and cross-references in the material. About this edition.