Test Description
The numbers below refer to the step numbers on the diagnostic table.
5
Obtaining rotational speed for the components rotating at tire/wheel speed is critical to systematically eliminating specific vehicle component groups. These component rotational speeds can be generated by using an electronic vibration analyzer, or through calculating them manually.
10
Note. Be certain to OBSERVE for disturbances that match the customer's description FIRST, then look at the vibration analyzer frequency which corresponds with that disturbance.
Proper location of the vibration analyzer sensor onto the component which is most excited by the vibration disturbance is critical to obtaining an accurate frequency reading.
This test will duplicate virtually any disturbance which occurs while the vehicle is in motion.
11
Accelerate to a speed high enough above the speed of the disturbance to allow for the time needed to shift into NEUTRAL and for the engine to decrease in RPM to idle speed, before coasting down through the disturbance range.
12
This test will either eliminate or confirm the engine as a contributing cause of the customer concern.
| Step | Action | Yes | No |
|---|---|---|---|
| Refer to ROAD TEST WARNING . | |||
| 1 | Did you review the Diagnostic Starting Point - Vibration Diagnosis? | Go to Step 2 | Go to VIBRATION DIAGNOSIS, STARTING POINT, AND CORRECTION |
| 2 | Did the customer concern indicate that the vibration occurs ONLY while the vehicle is standing still? | Go to Step 6 | Go to Step 3 |
| 3 | Visually inspect the tire and wheel assemblies, steering components and suspension components for any possible faults. Are the tire and wheel assemblies, steering components and suspension components in good working condition? | Go to Step 5 | Go to Step 4 |
| 4 | NOTE: Do NOT operate the vehicle until the faults are corrected. Correct the faults with the tire and wheel assemblies, steering components, and/or the suspension components before proceeding.Did you correct the faults with the tire and wheel assemblies, steering components, and/or the suspension components? | Go to Step 5 | Go to Step 3 |
| 5 | Obtain the drive axle final drive ratio. If the vibration analyzer has suitable software, obtain the transmission gear ratios. If the a vibration analyzer is not available, take note of the tire size on each axle, then calculate the tire rotational speed for each size tire used. Refer to COMPONENT ROTATIONAL SPEED CALCULATION . Did you obtain the powertrain ratios for use with the vibration analyzer, or calculate the component rotational speeds, if a vibration analyzer is NOT available? | Go to Step 6 | |
| 6 | Install a scan tool. With the scan tool, bring up the Powertrain Control Module data list and select Engine Speed. Is the scan tool operating properly? | Go to Step 7 | DIAGNOSTIC STARTING POINT - VEHICLE |
| 7 | Using a vibration analyzer is the preferred method for gathering necessary vibration frequency data. If a vibration analyzer is not available, the necessary vibration frequency data will have to be obtained based on symptoms observed during testing. Review SYMPTOMS - VIBRATION DIAGNOSIS AND CORRECTION to become familiar with the possible frequency ranges. Review SYMPTOMS - VIBRATION DIAGNOSIS AND CORRECTION , as necessary throughout the remainder of diagnostics. Is a vibration analyzer available for use? | Go to Step 8 | Go to Step 9 |
| 8 | Install the vibration analyzer. Is the vibration analyzer operating properly? | Go to Step 9 | Check the Vibration Analyzer |
| 9 | Did the customer concern indicate that the vibration occurs ONLY while the vehicle is standing still? | Go to VIBRATION ANALYSIS - ENGINE | Go to Step 10 |
| 10 | Install the vibration analyzer sensor, if available, to the component identified by the customer as most respondent to the vibration. If no component was identified, install the vibration analyzer sensor, if available, to the steering column. You may have to move the sensor to other locations later. Select a smooth, level road and slowly accelerate the vehicle up to highway speed. Observe the vehicle for disturbances that match the customer's description and note the following conditions: The vehicle speed The engine RPM The transmission gear range and the specific gear The vibration frequency reading, if detected by the vibration analyzer The feel and/or sound of the disturbance If the vibration seems to excite a particular component of the vehicle more than the steering column, then move the vibration analyzer sensor, if available, onto that component and repeat steps 2 and 3 . Were you able to duplicate the customer's concern? | Go to Step 11 | Go to VIBRATION DIAGNOSTIC AIDS |
| 11 | Accelerate the vehicle to a speed higher than the speed at which the disturbance occurs. NOTE: If the vehicle is equipped with an automatic transmission, let the vehicle coast to a stop before shifting back into gear. Shift the vehicle into NEUTRAL and allow the vehicle to coast down through the disturbance range. Does the disturbance still occur while coasting-down in NEUTRAL? | Go to Step 13 | Go to Step 12 |
| 12 | Select a smooth, level road and slowly accelerate the vehicle up to the speed at which the disturbance occurs. Decelerate and safely downshift by one gear range. Operate the vehicle at the same VEHICLE SPEED at which the disturbance occurs. Does the same disturbance still occur while going the same vehicle speed in a lower gear range? | Go to VIBRATION ANALYSIS - HUB AND/OR AXLE INPUT | Go to VIBRATION ANALYSIS - ENGINE |
| 13 | If the vibration analyzer is not available, refer to SYMPTOMS - VIBRATION DIAGNOSIS AND CORRECTION . Did the vibration analyzer detect a dominant frequency? | Go to Step 14 | Go to SYMPTOMS - VIBRATION DIAGNOSIS AND CORRECTION |
| 14 | If the vibration analyzer HAS the features, use the drive axle final drive ratio, the specific transmission gear ratio, and the engine RPM to make a comparison to the dominant frequency reading recorded. If the vibration analyzer does NOT have the features, compare the dominant frequency reading recorded to the component rotational data which you calculated previously. Does the frequency data clearly fall within the tire/wheel parameters ONLY? | Go to VIBRATION ANALYSIS - TIRE AND WHEEL | Go to SYMPTOMS - VIBRATION DIAGNOSIS AND CORRECTION |
| NOTE |
|---|
| Do NOT operate the vehicle until the faults are corrected. |
| NOTE |
|---|
| If the vehicle is equipped with an automatic transmission, let the vehicle coast to a stop before shifting back into gear. |
The numbers below refer to the step numbers on the diagnostic table
2
This test will determine the effect of turning input on the vibration.
6
This test will determine the effect of an initial heavy torque load on the vibration.
7
Damaged or worn wheel drive shafts may cause a noise or vibration that may be transferred into the passenger compartment.
8
Damaged or worn wheel bearings may cause a noise or vibration that may be transferred into the passenger compartment.
9
Damaged or worn suspension components may cause a noise or vibration that may be transferred into the passenger compartment.
10
Damaged or worn powertrain mounts and/or exhaust mounts may cause a noise or vibration that may be transferred into the passenger compartment.
11
Incorrect trim height may cause binding and/or interference between components that may produce a vibration.
| Step | Action | Yes | No |
|---|---|---|---|
| Refer to ROAD TEST WARNING . | |||
| 1 | Has the Vibration Analysis - Road Testing table been completed? | Go to Step 2 | Go to VIBRATION ANALYSIS - ROAD TESTING |
| 2 | Operate the vehicle at the speed of the vibration concern. While maintaining the concern speed, drive the vehicle through slow, sweeping turns - first in one direction, then in the other direction. Observe the vehicle for changes in the vibration disturbance. Select a smooth, level surface, such as an empty parking lot or a remote road. While maintaining the vehicle at the concern speed if possible, drive the vehicle through sharp turns; 360 degrees - first in one direction, then in the other direction. Observe the vehicle for changes in the vibration disturbance. Did the characteristics of the vibration change significantly-become worse or go away-during these steps? | Go to Step 3 | Go to Step 6 |
| 3 | Did you hear a clicking noise and/or feel a shudder during these steps? | Go to Step 7 | Go to Step 4 |
| 4 | Did you hear a growling noise during these steps? | Go to Step 8 | Go to Step 5 |
| 5 | Did you hear a popping noise during these steps? | Go to Step 9 | Go to Step 12 |
| 6 | With the vehicle at a stand-still, apply the regular brake and place the transmission in the lowest forward gear. NOTE: Do not accelerate so that the wheels screech, slip or jump. This will affect the results of the test. Release the regular brakes and accelerate aggressively to 32 km/h (20 mph). Observe the vehicle for changes in the vibration disturbance. Did you feel a shudder or shaking during these steps? | Go to Step 7 | Go to VIBRATION DIAGNOSTIC AIDS |
| 7 | Inspect the wheel drive shafts, if equipped, for damage, abnormal and/or excessive wear. If the inspection indicated that a wheel drive shaft is damaged, abnormally and/or excessively worn, replace the shaft. Did you find and correct a condition? | Go to Step 12 | Go to Step 9 |
| 8 | Inspect the wheel bearings for wear and/or damage. Replace any of the wheel bearings found to be worn and/or damaged. Did you find and correct a condition? | Go to Step 12 | Go to VIBRATION DIAGNOSTIC AIDS |
| 9 | Inspect the following suspension components for wear, damage, looseness and/or possible contact with other vehicle components: Struts/shock absorbers Springs Bushings Insulators Replace any of the suspension components found to be worn, damaged, loose and/or contacting other vehicle components. Did you find and correct a condition? | Go to Step 12 | Go to Step 10 |
| 10 | Inspect the powertrain mounts-engine, transmission, transfer case, and direct-mount differential, if equipped-and any powertrain braces for the following conditions: Loose and/or missing fasteners Improper alignment Cracked, dry-rotted, and/or oil-soaked insulators Twisted, broken, torn, and/or collapsed insulators Bent, twisted, and/or deformed brackets Replace powertrain mounts as necessary. Inspect the exhaust system components for the following: Loose and/or missing fasteners Heat Shields Joints and/or couplings: Nuts, bolts, studs, clamps, straps Bracket and/or insulator mounting Inadequate clearance to body and/or chassis components Inspect with the exhaust system both COLD and HOT; in NEUTRAL, FORWARD and REVERSE gears Improper alignment Disconnected and/or missing insulators Cracked, dry-rotted, and/or oil-soaked insulators Stretched, twisted, broken, torn, and/or collapsed insulators Bent, twisted, cracked, and/or deformed brackets Repair, replace, and/or realign exhaust system components as necessary. Did you find and correct a condition? | Go to Step 12 | Go to Step 11 |
| 11 | Inspect the vehicle trim height and adjust as necessary. Refer to TRIM HEIGHT INSPECTION . Did you find and correct a condition? | Go to Step 12 | Go to VIBRATION DIAGNOSTIC AIDS |
| 12 | Install or connect any components that were removed or disconnected during diagnosis. Perform the Vibration Analysis - Road Testing table. Refer to VIBRATION ANALYSIS - ROAD TESTING . Is the vibration still present? | Go to Step 2 | System OK |
| NOTE |
|---|
| Do not accelerate so that the wheels screech, slip or jump. This will affect the results of the test. |
The numbers below refer to the step numbers on the diagnostic table.
2
If powertrain related DTCs are present, there may be a powertrain performance condition present which could be a contributing cause to the customer's concern.
5
Making comparisons of the customer's vehicle with an equally equipped, same model year and type, KNOWN GOOD vehicle will help determine if certain disturbances may be characteristic of a vehicle design.
| Step | Action | Yes | No |
|---|---|---|---|
| Refer to WORK STALL TEST WARNING . | |||
| 1 | Has the Vibration Analysis - Road Testing table been completed? | Go to Step 2 | Go to VIBRATION ANALYSIS - ROAD TESTING |
| 2 | Using a scan tool, determine if any DTCs are set. Were any DTCs set? | Go to VIBRATION DIAGNOSIS, STARTING POINT, AND CORRECTION | Go to Step 3 |
| 3 | Block the front wheels. Apply BOTH the service brakes and the park brake. With the scan tool and an electronic vibration analyzer, if available, still installed, start the engine. Place the transmission in NEUTRAL or PARK. Slowly increase the engine RPM to the level at which the disturbance is most noticeable. Record the engine RPM obtained on the scan tool and the most dominant frequency reading if obtained on the vibration analyzer, if available. Place the transmission in DRIVE. Slowly increase the engine RPM to the level at which the disturbance is most noticeable. Record the engine RPM obtained on the scan tool and the most dominant frequency reading if obtained on the vibration analyzer, if available. If no frequency data was obtained, or if the vibration analyzer is not available, place the transmission into REVERSE, then repeat steps 8 and 9 . Reverse-loading of the powertrain may increase or change the characteristics of the vibration. Were you able to duplicate the customer's concern? | Go to Step 4 | Go to VIBRATION DIAGNOSTIC AIDS |
| 4 | Did the vibration analyzer detect a dominant frequency, or was a significant vibration present? | Go to VIBRATION ANALYSIS - ENGINE/ACCESSORY ISOLATION | Go to Step 5 |
| 5 | Compare the test results of the customer's vehicle to the results of the same tests run, at the same engine RPM, on an equally-equipped, same model year and type, KNOWN GOOD vehicle. Refer to VEHICLE-TO-VEHICLE DIAGNOSTIC COMPARISON . Install a scan tool into the known good vehicle. Install a vibration analyzer, if applicable, in the car that is in good condition. Place the sensor in the same location as in the customer's car. Block the front wheels. Apply BOTH the service brakes and the park brake. Start the engine. Place the transmission in NEUTRAL or PARK. Slowly increase the engine RPM to the level at which the disturbance was most noticeable in the customer's vehicle. Record the engine RPM obtained on the scan tool and the most dominant frequency reading if obtained on the vibration analyzer, if available. Place the transmission in DRIVE. Slowly increase the engine RPM to the level at which the disturbance was most noticeable in the customer's vehicle. Record the engine RPM obtained on the scan tool and the most dominant frequency reading if obtained on the vibration analyzer, if available. If no frequency data was obtained, or if a vibration analyzer is not available, place the transmission into REVERSE, then repeat steps 10 and 11 . Reverse-loading of the powertrain may increase or change the characteristics of the vibration. Did both of the vehicles exhibit the same characteristics? | Go to VIBRATION DIAGNOSTIC AIDS | Go to VIBRATION ANALYSIS - ENGINE/ACCESSORY ISOLATION |
The numbers below refer to the step numbers on the diagnostic table.
5
A loose, damaged, misaligned, or defective powertrain insulator and/or bracket may create a transfer path into the passenger compartment.
6
A loose, damaged, misaligned, or defective exhaust system insulator and/or bracket may create a transfer path into the passenger compartment.
7
Incorrectly seated and/or aligned powertrain components and/or exhaust system components may create a transfer path into the passenger compartment.
8
Non-rotating engine driven accessory component systems can no longer produce a unique disturbance.
9
Non-rotating engine driven accessory components can no longer produce a unique disturbance. If a disturbance is still present, but the characteristics have been altered, it is possible that these component systems are acting as a transfer path for engine firing frequency or a first order engine disturbance.
If a disturbance is still present, but the characteristics have NOT been altered, it is NOT likely that these component systems are acting as a transfer path for engine firing frequency or a first order engine disturbance.
10
If the mark placed on the face of an engine driven accessory pulley seems to stand still while running this test, then that accessory system is either responding to an existing frequency, such as engine firing pulses, or creating a disturbance.
11
A loose, damaged, misaligned, or defective engine driven accessory system insulator and/or bracket may create a transfer path into the passenger compartment.
12
Removing the engine driven accessory and bracket, or brackets from the engine allows a thorough inspection to determine if any conditions are present that may create a transfer path into the passenger compartment.
| Step | Action | Yes | No |
|---|---|---|---|
| Refer to WORK STALL TEST WARNING . | |||
| 1 | Were you sent here from the Vibration Analysis - Engine table? | Go to Step 2 | Go to VIBRATION ANALYSIS - ENGINE |
| 2 | Is an electronic vibration analyzer available? | Go to Step 3 | Go to Step 5 |
| 3 | Using the engine RPM and frequency data recorded for the customer's vehicle, determine the order of engine rotation to which the disturbance is related. Determine the possible causes of the disturbance as it relates to a specific order of engine rotation. Refer to ENGINE ORDER CLASSIFICATION . Does the Engine Order Classification table indicate that the disturbance is of the same order as the engine firing frequency? | Go to Step 5 | Go to Step 4 |
| 4 | Does the Engine Order Classification table indicate that the disturbance is likely related to engine driven accessories? | Go to Step 8 | Go to Step 5 |
| 5 | Inspect the powertrain mounts-engine, transmission, transfer case, and direct-mount drive axle, if equipped-and any powertrain braces for the following conditions: Loose and/or missing fasteners Improper alignment Cracked, dry-rotted, and/or oil-soaked insulators Twisted, broken, torn, and/or collapsed insulators Bent, twisted, and/or deformed brackets Realign or replace powertrain mounts as indicated by the inspection. Did you find and correct a condition? | Go to Step 13 | Go to Step 6 |
| 6 | Inspect the exhaust system components for the following: Loose and/or missing fasteners Heat Shields Joints and/or couplings: Nuts, bolts, studs, clamps, straps Bracket and/or insulator mounting Inadequate clearance to body and/or chassis components Inspect with the exhaust system both COLD and HOT; in NEUTRAL, FORWARD and REVERSE gears. Improper alignment Disconnected and/or missing insulators Cracked, dry-rotted, and/or oil-soaked insulators Stretched, twisted, broken, torn, and/or collapsed insulators Bent, twisted, cracked, and/or deformed brackets Repair, replace, and/or realign exhaust system components as indicated by the inspection. Did you find and correct a condition? | Go to Step 13 | Go to Step 7 |
| 7 | Check for incorrectly seated and/or aligned powertrain components and/or exhaust system components. Did you complete the procedure? | Go to Step 13 | |
| 8 | WARNING: Do not run the engine for longer than 60 seconds with the accessory drive belts, or belts removed. If this is not done, overheating and/or damage can result. Remove the engine drive belt, or belts. Block the front wheels. Apply BOTH the service brakes and the park brake. With the scan tool still installed, start the engine. Place the transmission in NEUTRAL or PARK. Increase the engine RPM to the level recorded during duplication of the disturbance. Allow the engine to idle, then place the transmission in DRIVE. Increase the engine RPM to the level recorded during duplication of the disturbance. Turn OFF the ignition. Install the engine accessory drive belt, or belts. Was the disturbance significantly reduced or eliminated? | Go to Step 10 | Go to Step 9 |
| 9 | Were the characteristics of the disturbance altered but still present? | Go to Step 11 | Go to Step 15 |
| 10 | Mark the face of the suspected accessory pulleys, including any related idler pulleys, near the outer edge with a paint mark. Install an inductive pickup to the vibration analyzer. Block the front wheels. Apply BOTH the service brakes and the park brake. With the scan tool and the vibration analyzer, still installed, start the engine. Enter the recorded frequency of the disturbance as the initial frequency for strobe operation. Have an assistant place the transmission in NEUTRAL or PARK. Slowly increase the engine RPM to the level recorded during duplication of the disturbance, then maintain that speed. Using the vibration analyzer, check each of the suspected accessory pulleys to determine if any of them is related to the frequency of the disturbance. Check each of the accessory systems, both engaged and under maximum load and disengaged or under minimum load. Allow the engine to idle, then place the transmission in DRIVE. Slowly increase the engine RPM to the level recorded during duplication of the disturbance, then maintain that speed closely. Using the vibration analyzer, check each of the suspected accessory pulleys to determine if any of them is related to the frequency of the disturbance. Check each of the accessory systems, both engaged and under maximum load and disengaged or under minimum load. Turn OFF the ignition. Did you identify an engine driven accessory system as being related to the frequency of the disturbance? | Go to Step 11 | Go to VIBRATION DIAGNOSTIC AIDS |
| 11 | Inspect the components of the engine driven accessory system for the following: Loose and/or missing fasteners Heat Shields, if equipped Joints and/or couplings: Nuts, bolts, studs, clamps, straps Bracket and/or insulator mounting Inadequate clearance to body and/or chassis components Inspect with the accessory system both under a LOAD and NOT loaded Improper alignment Bent or damaged pulleys Disconnected and/or missing insulators Cracked, dry-rotted, and/or oil-soaked component insulators Stretched, twisted, broken, torn, and/or collapsed component insulators Bent, twisted, cracked and/or deformed component brackets Repair, replace, and/or realign the engine driven accessory system components as indicated by the inspection. Did you find and correct a condition? | Go to Step 13 | Go to Step 12 |
| 12 | Remove the engine driven accessory and bracket, or brackets from the engine. Thoroughly inspect the accessory bracket, or brackets, bolts/nuts/studs, and the accessory itself for signs of the following: Bent, twisted, cracked and/or deformed conditions Replace any of the components found to exhibit any of these conditions. Reinstall the components to the engine. Did you find and correct a condition? | Go to Step 13 | Go to Step 17 |
| 13 | Check the vehicle to determine if the disturbance is now significantly reduced or eliminated. Perform the following steps: Install a scan tool into the customer's vehicle. Install a vibration analyzer, if available, into the customer's vehicle; place the sensor in exactly the same location as it was originally placed in the vehicle. Block the front wheels. Apply BOTH the service brakes and the park brake. Start the engine. Place the transmission in NEUTRAL or PARK. Slowly increase the engine RPM to the level at which the disturbance was most noticeable. Record the engine RPM obtained on the scan tool and the most dominant frequency reading if obtained on the vibration analyzer, if available. Place the transmission in DRIVE. Slowly increase the engine RPM to the level at which the disturbance was most noticeable. Record the engine RPM obtained on the scan tool and the most dominant frequency reading if obtained on the vibration analyzer, if available. If the disturbance has been significantly reduced or eliminated, confirm the results by placing the transmission into REVERSE, then repeat steps 10 and 11 . Reverse-loading of the powertrain may increase or change the characteristics of the vibration. Has the disturbance been significantly reduced or eliminated? | Go to Step 18 | Go to Step 14 |
| 14 | Have you investigated powertrain isolation as a possible cause of the disturbance? | Go to Step 15 | Go to Step 5 |
| 15 | Have you investigated engine driven accessories as a possible cause of the disturbance? | Go to VIBRATION ANALYSIS - ENGINE BALANCE | Go to Step 16 |
| 16 | Is a vibration analyzer available? | Go to Step 8 | Go to VIBRATION DIAGNOSTIC AIDS |
| 17 | Replace the engine driven accessory component causing the disturbance. Did you complete the replacement? | Go to Step 18 | |
| 18 | Install or connect any components that were removed or disconnected during diagnosis. Perform the Vibration Analysis - Road Testing table. Refer to VIBRATION ANALYSIS - ROAD TESTING . Is the disturbance still present? | Go to Step 2 | System OK |
| WARNING |
|---|
| Do not run the engine for longer than 60 seconds with the accessory drive belts, or belts removed. If this is not done, overheating and/or damage can result. |
General Information
The car's display indicates when a service is due. When this message is displayed it is primarily due to driving conditions, such as cold starts, short journeys, driving with a trailer, driving with heavy loads, etc. The distance covered and time since previous service interval determines when it is time for a service. This means that the interval between services can vary considerably.
Note. Only use Saab specification engine oil. See RECOMMENDED OIL GRADE