2017 Ford F-150 Steering Gear: EPAS Faults, Wheelbase Warnings, and Replacement Guide
A deep dive into the common electronic steering failures on the 2017 F-150, including the critical wheelbase-specific part differences you must know before buying.
- The steering gear is specific to your truck's wheelbase. You MUST verify your wheelbase (e.g., 122.0" or 141.0") and match it to the correct part number.
- A replacement steering gear (new, used, or reman) MUST be electronically programmed to the vehicle using a tool like FORScan to function.
- Failure is almost always electronic, presenting as a "Steering Assist Fault" message and a sudden loss of power steering.
- Check for Safety Recall 17S23 regarding corroding heat shield fasteners, which can cause the steering gear to overheat and fail.
Symptoms of a Failing Steering Gear
Failure of the EPAS system in the 2017 F-150 is almost always an electronic issue, not a mechanical one. The symptoms are often sudden and can be alarming. The most common sign is a dashboard warning message stating "Steering Assist Fault Service Required." This is typically accompanied by an immediate and total loss of power steering, making the truck extremely difficult to turn.
- Sudden Heavy Steering: The steering wheel becomes very hard to turn, as if the truck has no power steering at all. This is the primary symptom.
- Cascade of Warning Lights: When the EPAS system fails, it's common for a host of other warning lights to appear simultaneously, including ABS, AdvanceTrac, Hill Start Assist, and Pre-Collision Assist. This happens because these systems are all interconnected and rely on data from each other.
- Intermittent Problems: Before a complete failure, you might experience intermittent issues. This can include the steering feeling heavy or "notchy" at times, a slight pull to one side, or the warning lights coming on and then disappearing after restarting the truck.
- Clicking Noises: Some owners report hearing clicking noises from the vehicle even when it's turned off, which may be related to the Power Steering Control Module (PSCM) which is powered at all times.
Pro Tip: Before assuming the entire steering rack has failed, check for simpler issues. A low or failing battery, a bad ground connection, or a faulty wheel speed sensor can sometimes cause the same cluster of warning lights and steering fault messages. Also, check the large fuse for the EPAS module in the under-hood fuse box.
Known Issues, Recalls, and TSBs
Safety Recall 17S23: EPAS Heat Shield Fasteners
A significant recall was issued for some 2017 F-150s related to the steering gear. The fasteners used to secure the EPAS heat shield could corrode and fail. If this happens, the heat shield can fall off, exposing the steering gear's electrical connectors to excessive heat from the engine and exhaust. This can melt the connectors, leading to a loss of communication and a sudden failure of the power steering assist. The fix involves inspecting and replacing the fasteners with corrosion-resistant ones.
Other Service Actions
Ford's official records also show a service campaign for "Power steering control module reprogramming" for this model year, indicating that software updates are sometimes required to fix certain issues. Additionally, a Technical Service Bulletin (TSB) was released for 2015-2017 models that experienced intermittent steering assist loss, directing technicians to inspect a specific wiring harness near the A/C compressor pulley for damage.
Warning: The most critical factor when ordering this part is your truck's wheelbase. The steering gear is NOT one-size-fits-all. The part numbers HL3Z-3504-E, HL3Z-3504-L, and STE-595 are specifically for models with a 122.0-inch or 141.0-inch wheelbase. Other wheelbases (like 145", 157", or 163") use different part numbers. You MUST verify your vehicle's wheelbase and match it to the correct part number before purchasing.
Buying a Used 2017 F-150 Steering Gear
Given the high cost of a new OEM steering gear, a used or recycled unit is a very popular and cost-effective option. Since failures are typically electronic, a physically undamaged used rack from a lower-mileage vehicle is often a reliable replacement. Here’s what to check:
- Verify the Part Number: This is the most important step. Get the part number from the seller and confirm it matches the correct part for your truck's specific wheelbase. Do not rely on visual comparison alone.
- Inspect the Electrical Connectors: Carefully examine the electrical connectors on the EPAS motor and module. Look for any signs of melting, corrosion, or damaged pins. This is a common failure point, especially if the heat shield was missing.
- Check the Housing: Inspect the main body of the steering rack for any cracks, dents, or signs of heavy impact. A damaged housing could indicate the donor vehicle was in a significant front-end collision.
- Examine the Bellows Boots: The rubber boots on either end of the rack protect the inner tie rods. Ensure they are not torn or ripped. Damaged boots allow dirt and water in, which can destroy the internal seals and moving parts.
- Input Shaft Splines: Check the splines on the input shaft where the steering column connects. They should be clean and well-defined, not twisted or stripped.
- Plan for Programming: Remember that ANY replacement steering rack—new, remanufactured, or used—will need to be electronically configured to your truck. This is not optional. If you do not perform the programming, you will get a "Initial Configuration Not Complete" error and the steering assist will not work correctly.
Replacement Overview & Difficulty
Replacing the steering gear is a mechanically involved job that also requires specific electronic tools. It is a challenging task for a DIY mechanic.
- Installation: The physical replacement involves lifting the front of the vehicle, removing the front wheels, disconnecting the outer tie rod ends from the steering knuckles, unbolting the steering shaft, and then unbolting the rack itself from the subframe. Access can be tight.
- Programming: After the new rack is installed, it must be programmed to the vehicle. This is typically done with a diagnostic tool like FORScan (a popular choice for DIYers) or the Ford dealership's IDS software. The process involves loading the vehicle's "As-Built" data into the new Power Steering Control Module (PSCM) and calibrating the steering angle sensor.
- Alignment: A full four-wheel alignment is required after replacement to ensure the vehicle drives straight and to prevent abnormal tire wear.
Cost Comparison: New vs. Used vs. Remanufactured
| Part Type | Estimated Cost |
|---|---|
| New OEM (Dealer) | $1,300 - $2,200+ |
| New Aftermarket | $900 - $1,500 |
| Remanufactured | $800 - $1,100 (plus a core charge of $400+) |
| Used OEM | $350 - $700 |
| Shop Labor | $250 - $450 for installation, plus alignment and programming fees. |
Frequently Asked Questions (FAQ)
Do I have to program a replacement steering rack?
Yes, absolutely. The Power Steering Control Module (PSCM) is integrated into the steering rack assembly. When you install a different rack, the new module must be configured with your truck's specific data and calibrated. Without this step, it will not function and will display a "Steering Assist Fault."
Can I just replace the EPAS motor or module?
No, the electric motor and the control module are considered integral parts of the steering gear assembly. They are not typically sold separately, and replacement requires a complete steering gear unit.
My steering failed, but all my warning lights came on. Is it something else?
This is normal behavior for an EPAS failure. The steering system shares data with the ABS, traction control (AdvanceTrac), and other safety systems. When the steering module fails and stops communicating, all dependent systems will also report a fault. The root cause is very likely the steering system itself.
What is the difference between part numbers HL3Z-3504-E and HL3Z-3504-L?
Part number HL3Z-3504-L is a superseding part number that replaces HL3Z-3504-E. This means Ford has updated the part, and -L is the newer, recommended version. Both are specified for the 122" and 141" wheelbases. STE-595 is the Motorcraft service part number for the same application.
Technical Specifications
OEM Part Numbers: HL3Z-3504-E HL3Z-3504-L STE-595
System Type: Electric Power Assisted Steering (EPAS). Fitment is specific to vehicle wheelbase. For part numbers HL3Z-3504-E/L and STE-595, fits 122.0-inch and 141.0-inch wheelbases only.
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The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.
- Ford F-150:
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- Symptoms of a Failing Steering Gear
- Known Issues, Recalls, and TSBs
- Safety Recall 17S23: EPAS Heat Shield Fasteners
- Other Service Actions
- Buying a Used 2017 F-150 Steering Gear
- Replacement Overview & Difficulty
- Cost Comparison: New vs. Used vs. Remanufactured
- Frequently Asked Questions (FAQ)
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