Addressing SUV/CUV Steering Issues
Today’s SUVs (sport utility vehicles) and CUVs (crossover utility vehicles) face the same steering system issues as other types of vehicles, in terms of steering system component wear, braking system operation and wheel alignment concerns.
However, with the advent of electric power steering systems, AWD systems and potential overloading due to (in some cases) increased cargo capacity, we decided to take a closer look at potential steering-related issues and preventing comebacks following service. Included here are both basic system concerns as well as a few vehicle-specific issues. Note that the vehicle-specific examples were gleaned from Mitchell 1’s ProDemand site.
Any technician understands the importance of lower ball joints. As a ball joint wears, the ball becomes loose within its socket, allowing the ball and stud to move excessively. This is often represented by a clunking noise from the front suspension as the vehicle travels over bumps or a rough road.
Loose or damaged ball joints can also cause excessive wheel vibration and uneven tire wear at the inner and outer shoulders. Naturally, premature shoulder wear can also be caused by under-inflation, but if inflation is correct, suspect the ball joint(s).
Worn ball joints also can result in wandering, where the vehicle tends to steer on its own left or right, causing the driver to counter-steer to compensate, as worn ball joints can allow wheel camber angles to change erratically. Obviously, if a ball joint fails and separates, the wheel angle can change abruptly and result in loss of connection with the lower control arm.
Typical causes for ball joint damage include inferior materials, such as synthetic liners between the stud ball and bearing cavity, moisture or dirt entering the joint due to an inferior, poorly installed or damaged dust boot, or lack of lubrication which eventually leads to sticking, seizing or grinding of the joint and possible failure.
Whenever replacing a ball joint, it’s always preferable to install a quality aftermarket joint that features a pre-installed dust boot that has been properly seated, a serviceable zerk fitting, allowing for future flushing and introduction of fresh grease, and a powdered metal gusher bearing that provides constant lubrication.
Some OEM ball joints feature a polymer bearing and a non-hardened stud and inferior boot designs that may allow water and road contamination to enter and corrode the ball. Examples include but are not limited to 1997-2002 Ford Expedition and 1995-2005 Explorer models as well as 1996-2002 Lincoln Navigators. Improved aftermarket ball joints are readily available to address these concerns.
High quality ball joints designed to withstand abuse and provide durability are readily available from sources such as Moog’s Problem Solver designs.
In some cases, where customers “upgrade” to larger wheel diameters and wide tires with shorter sidewall height, ball joints and other suspension and steering-related components may be subject to increased wear as the shorter sidewalls offer reduced deflection and a subsequently stiffer tire-to-road impact.
Loaded ball joints experience vehicle weight, typically at the lower control arm at the lower arm on an SLA (short/long arm) suspension, which also must be able to pivot in relation to steering linkage and the steering knuckle.
On a twin-arm suspension, the upper ball joint serves as a follower joint. A strut suspension uses a follower ball joint to connect the lower control arm, steering knuckle and the strut. The upper strut mount assembly features a thrust-type bearing to support the weight of the vehicle and allow the steering linkage to rotate the strut and steering knuckle. Check for both axial and lateral runout. Axial runout of a ball joint basically refers to the in/out movement of the ball joint stud and ball relative to its ball socket as the stud and ball moves in-out of the socket. Lateral runout refers to movement of the stud ball side-to-side within the socket.
To check for axial runout on an SLA suspension, support vehicle weight by lifting at the lower control arm. Place a pry bar between the bottom of the tire and the ground to first determine if any axial movement is present. When dealing with a MacPherson strut front suspension, lift the vehicle by the frame or rocker panel support area and test in the same manner.
If lower ball joint axial play is suspected, attach a dial indicator to the lower control arm and position the dial gauge in a vertical position on a clean flat spot at the top of the spindle steering knuckle. Preload the dial indicator by about 0.050 inch and zero the gauge. While prying up/down, if axial movement exceeds the manufacturer specification limit, the ball joint (or the lower control arm assembly, depending on the design), should be replaced. Naturally, always refer to the runout limit specifications listed for the specific vehicle. Manufacturer specifications regarding axial or lateral joint runout limits will vary from about 0.020 inch to as much as 0.100 inch or more.
VEHICLE PULLS LEFT OR RIGHT
A directional pull can be caused by a number of variables, including a worn or broken coil spring, worn control arm bushings, a worn/loose tie rod, wheel alignment issues and/or a brake issue.
If the pull occurs only when braking, the cause is most likely a caliper issue, where the left or right caliper is not applying the same pressure on its rotor.
Obviously, incorrect wheel alignment angles can easily influence steering stability, wander, directional pulling during cruise or braking, and premature tire tread wear. The relatively higher sprung weight of larger SUVs adds increased stress to various steering system components, potentially resulting in faster wear rates of system components such as tie rods, control arm bushings, lower ball joints, springs and possibly faster tire wear issues.
A pre-alignment check, as with any vehicle, is important to detect worn or damaged steering components prior to an attempt to adjust wheel alignment. Take particular note of any cargo or the presence of a trailer hitch. Have a conversation with the customer with regard to cargo loads (if high loads are expected, and how often these loads are carried). If a trailer hitch is featured, ask the customer if he or she pulls a trailer, and if so, how often, and the trailer tongue weight. This can influence the front wheel alignment when the vehicle is exposed to heavy rear axle loads. If the vehicle tends to pull or wander while driving in a straight line and/or under braking, incorrect/uneven camber or caster angles may be suspect.
For example, if the right front wheel features positive camber and the left front wheel features negative camber angle, the vehicle will always try to pull to the left. If the caster angles are out of specification, the vehicle will tend to pull in the direction of the side with the least positive caster.
TIRE WEAR AND INFLATION
Naturally, one of the basic checks during most service involves inspecting tire condition and inflation pressure. Uneven and/or premature tread wear can result from a number of issues including lower ball joint looseness, improper wheel alignment angles (toe issues resulting in feathered wear, camber issues resulting in excessive inner or outer tread shoulder wear), and inflation issues where the center tread wear is excessive due to over-inflation, or both inner and outer shoulder wear due to under-inflation. Worn or damaged shock absorbers or struts can result in choppy tread wear due to inadequate compression and rebound control.
Considering today’s across-the-board inclusion of tire pressure monitoring systems (TPMS), inflation issues shouldn’t be as much of a concern, yet there are customers out there who tend to ignore the TPMS in-dash alerts.
TIE ROD ENDS
A worn tie rod end will allow the wheel toe angle to fluctuate/change, causing uneven tire wear, vibration and wander. If a tie rod end fails, the wheel will have no directional control and will toe in or out fully, resulting in loss of steering control and a potential crash.
Always replace with the highest quality tie rod ends, always install a new locking nut and tighten the stud nut at the steering knuckle to factory specifications. Do not allow the ball and stud to rotate when tightening the nut.
Most new tie rod ends feature an anti-rotation male hex at the tip of the stud, allowing you to hold the shaft stationary while initially tightening the nut.
Once the tapered stud has interference-fit into the steering knuckle hole, use a torque wrench to final-tighten the nut. Note that SUVs often use beefier components and require increased nut torque, so always refer to and follow factory torque specifications.
Vehicle “wandering” can be caused by any of several potential concerns, including uneven tire inflation (where the vehicle tends to drift to one side or the other), low tire pressure that allows excessive sidewall flex and can easily increase steering effort, loose/worn tie rod ends and/or ball joints, damaged or missing anti-sway bar end links or bushings, and incorrect wheel alignment.
Worn or damaged shock absorbers can contribute to wandering, as spring oscillations are not properly controlled, potentially causing the driver to continually make steering corrections when travelling over bumpy or uneven roads.
Worn/contaminated/failing CV joints can easily cause a vibrational issue that the customer may blame on a wheel imbalance, prior to or in addition of joint failure, which would render the vehicle un-drivable. Whenever a vehicle that features CV joints is on a lift, inspect the boots for tears, cracks or splits or boot clamps that are dislodged.
If grease has migrated out of the boot, or if contaminants have entered the boot, the CV joint should be replaced. Considering today’s ready availability of complete CV axle assemblies, it’s usually more advantageous (considering the expense of labor time) to simply replace the shaft assembly as opposed to rebuilding or replacing only the offending joint.
Electronic power steering systems (EPS) are increasingly being used in today’s vehicles. An all-electric power steering system, as opposed to a hybrid system that featured an electric-over hydraulic function, works by incorporating information with the EPS control unit, EPS motor, reduction gear, and torque sensor.
A pinion gear provides the power assist by rotating the pinion gear. The reduction gear is press fitted onto a set of splines on the pinion shaft and delivers the assist to the rack gear instead of pushing on the rack gear as in a hydraulic system.
In a rack steering system that incorporates electric assist, the steering gear itself is a manual rack with an electric motor mounted on the steering column or the rack. When the driver turns the wheel, a steering sensor detects the position and rate of rotation of the steering wheel. This information along with input from a torque sensor mounted in the steering shaft is sent to the power steering control module.
The system also uses other inputs such as vehicle speed sensors and information from the traction control system are factored in to determine how much steering assist is required. The control module then tells the motor to rotate the required amount, attached to the motor is the motor resolver sensor, which measures the rotation of the motor and sends the data to the EPS control module. Different road surfaces will require different amounts of steering assist.
- Normal mode — Left and right assist is provided in response to inputs and vehicle speed. During normal operation power assist levels will decrease as the vehicle speed increases.
- Assist limitation — Will occur if there is a problem with the information going back to the EPS control module, overheating of the EPS module or a malfunction with the controller area network.
- Assist off — System if turned off if there is a problem with any of the major EPS components.
Most systems malfunctions present problems such as:
- Heavy steering — Check torque sensor, power steering motor, speed sensors, powers steering ECU, and ECU source voltage.
- Uneven steering between right and left — Check calibration of torque sensor (built into steering column), power steering motor, power steering ECU or wheel alignment.
- Steering effort doesn’t decrease while driving — Check torque sensor, power steering motor, power steering ECU.
- Knocking when turning steering wheel — Steering intermediate shaft, ball joint.
- Noise or vibration in steering wheel — Check power steering gear, steering column.
- Squeaking — Power steering motor.
Following are a few vehicle-specific examples of steering related issues (courtesy of Mitchell 1):
Subaru announced a new EPS (electronic power steering) control module for 2012-2016 Impreza 2.0L, 2013-2017 Crosstrek and 2014-2017 Forester models. The new EPS control modules address a “limited number” of customer concerns regarding increased steering effort which may occur during freezing temperatures after a cold start. The cause has been identified as a frozen relay contact inside the control module. Illumination of the EPS warning lamp can also occur and a DTC C2532 may be stored. The new EPS control modules were incorporated into production starting with Crosstrek VIN HH276440 and Forester VIN JH401989.
ADD-ONS CAN CAUSE STEERING ISSUES
General Motors reports that aftermarket add-ons at the ALDL or DLC interface devices can cause issues related to high or low speed data bus traffic. One of the potential concerns is erratic electric power steering boost potentially associated with codes U2109, U2107, U2100, B1325 and C0000.
Other issues may involve reduced power messages and codes, Stabilitrak message and codes, C0561 stored in the EBCM leading to a traction control issue, no high speed LAN communication along with various communication U-codes, TCM in default mode (transmission may not shift for one key cycle), erratic gauge readings or flickering displays, SES, MIL or CEL light set and numerous DTC communication codes such as U0100, U0101, U186B and U1862.
Also, diesel power-up devices causing no power in 4WD low range, battery run-down, TPMS light illuminated and the inability to relearn TPMS, reduced propulsion power message in hybrids, service high voltage charging system message in hybrids, and various engine and transmission performance issues with the SES light set.
Plus radio not shutting off after vehicle shutdown, bus or LAN traffic staying active leading to battery discharge, problems reprogramming modules due to interference or the device not allowing the bus to power down, losing ONSTAR ability to provide diagnostic data and intermittent drivability issues.
HYUNDAI SANTA FE
On some 2013-2018 Santa Fe vehicles, a yoke noise may develop in the steering rack. A rattle type noise is heard when driving and turning the steering wheel, with the noise coming from the steering rack yoke support area.
1. Secure the steering wheel in the straight-ahead position to prevent damage to the clock spring. Do not allow the steering wheel to spin freely, in order to prevent damage to the clock spring. Use a steering wheel holding device such as the one listed in the service manual during alignment adjustments.
2. Remove the steering gearbox assembly from the vehicle.
3. Secure the steering rack in a vice with the yoke plug facing up. Remove any foreign substance or adhesive from around the rack housing and yoke plug. Be sure to protect the rack when securing to the vice using shop towels.
4. Remove the lock nut using the yoke lock nut tool and discard the original nut.
5. Loosen and remove the yoke plug and discard.
6. Remove the yoke spring, but do not discard it, as it will be re-used during assembly
7. Clean the threads and interior of the yoke plug housing with a clean rag and only isopropyl alcohol. Be sure to clean off any grease from the threads.
8. Remove the support yoke and discard.
9. Clean out any remaining debris from the threads and interior of the plug housing with compressed air (wear protective goggles when using compressed air).
10. Check that the new support O-rings are properly seated. Apply 3 grams of grease (1 full tube) on the center of the yoke liner. Be sure that the grease does not push out onto the housing threads when installing the support yoke. Apply a thin layer of grease on the outer diameter O-rings of the support yoke. Apply a thin layer of grease where the yoke spring sits in the support yoke.
11. Install the new support yoke. Make sure that the curve of the support yoke is aligned properly.
12. Reinstall the yoke spring.
13. Initially hand-tighten the new yoke plug.
14. Tighten the yoke plug to 36.8 ft.-lbs. (50 Nm), within 1 minute after initial hand tightening.
15. Create a single mark on the housing, which is aligned with the pre-existing mark on the yoke plug.
16. Rotate the yoke plug counter-clockwise until the blue yoke plug mark is aligned with the steering rack housing mark made in Step 15.
17. Hand tighten the lock nut until it contacts the surface of the rack housing.
18. While holding the yoke plug with a socket wrench, tighten the lock nut using a torque wrench, tightening to 40.5 ft.-lbs. (55 Nm).
19. Reinstall the rack and perform a front toe alignment.
GMC POWER STEERING MESSAGE
A bulletin released by GMC involves a service warning for ABS and/or traction control on 2015-2018 Yukon and Sierra models, with any of the following DTCs: B127B, U0077, U0121, U0126, U0131, U0139, U0151, U0401, U0415, U18A3, U2179 and/or U0428.
The conditions might include any of the following:
- ABS and/or TRAC warning light/message.
- Electric power steering issue.
- Backup/reverse camera inoperative.
- Loss of communication with EBCM, SDGM, SDM, SWPS, PSCM, PTO, HMI and/or SCM.
- Backup camera grid or guidance lines missing/inoperative.
- Vehicle settings icon grayed out.
These concerns could be caused by high resistance/open/short in the communication enable circuit 5986.
The BCM activates this circuit when the ignition key is in ACC, ON and START positions (there will be voltage present in the OFF position only for a short time until the BCM goes to sleep). The communication enable circuit wakes up the module for serial data bus communication. Circuit 5986 will have approximately 12 volts and should light a test light, but is not designed to handle heavier electrical loads like a headlight bulb.
Monitor the voltage on the communication enable circuit at any of the modules affected. If low voltage or no voltage is present when the concern occurs, inspect for open/high resistance/shorts on the circuit and repair as needed.
Circuit 5986 is a low amperage signal circuit and it may not be able to power certain test lights or bulbs. The use of a voltmeter and small bulb (example 194 bulb) is required to load test the circuit. With a battery charger/maintainer connected to the vehicle, attach one side of a 194 bulb to circuit 5986 (at the suspect module) and the other side to a good ground (battery negative).
Next, wake up the BCM by turning the headlights on or turning the ignition switch on, and make sure that the bulb lights. If the bulb does not light, inspect for high resistance/open/shorts in circuit 5986.
If the bulb does light, use a voltmeter and measure voltage across the 194 bulb to make sure that there is at least 11 volts. If not, inspect for high resistance/open/shorts in the circuit. A 194 bulb draws about 250 ma.
Attaching too much of a load to circuit 5986 will pull the voltage down below 11 volts and lead to misdiagnosis.
The BCM monitors circuit 5986 for an excessive amperage draw and will shut down the output on the circuit if it draws more than 0.88 amps (example: short to ground). ■