Electric Power Steering System Diagnosis Checklist

This electric power steering (EPS/EPAS) diagnosis checklist provides systematic procedures for modern electric power steering systems that have replaced hydraulic systems on most post-2010 passenger vehicles. EPS failures can present as heavy steering, intermittent assist loss, vibration, or warning lights. Most EPS faults require module-level scanning, torque sensor verification, and steering angle sensor calibration that cannot be diagnosed without appropriate scan tool capability. Aligned wit

Industry: Automotive Service
Frequency: Per Steering Complaint / Per EPS Warning Light
Estimated Time: 30-60 minutes
Role: ASE A4-Certified Technician / EPS Specialist
Total Items: 28
Compliance: ASE A4 Suspension and Steering Certification, FMVSS 203 and 204 (Steering Control), OEM EPS Calibration Procedures, SAE J3082 Electric Power Steering Standards, UK MOT Steering System Requirements

EPS Fault Code Retrieval and Initial Assessment

Retrieve EPS module codes before any mechanical inspection.

EPS/EPAS control module scanned with comprehensive scan tool (not basic OBD-II only)?
All EPS fault codes documented with freeze frame data?
Steering angle sensor (SAS) calibrated if vehicle has had alignment, steering, or suspension work recently?
EPS module supply voltage verified at specification (charging system issue can cause EPS faults)?
Current assist level and vehicle speed input verified working via scan tool live data?

Torque Sensor and Column Inspection

The torque sensor is the primary feedback device that tells EPS how much assist to provide.

Torque sensor signal plausible on scan tool live data when steering wheel turned?
No grinding, clicking, or rubbing noise from steering column during full lock turns?
Steering column not bent or damaged from prior collision?
Clock spring/spiral cable continuity verified (horn, airbag, and EPS torque sensor pass through)?
EPS motor not in thermal shutdown from excessive steering input (common after parking lot maneuvering)?

Steering Rack and Column Mechanical Inspection

Inspect mechanical components for wear or damage affecting steering feel.

Electric rack and pinion showing no torn rack boots or binding during lock-to-lock motion?
No excessive play at steering wheel input before rack responds?
Intermediate shaft U-joints or flexible coupler tight with no looseness or binding?
Tie rod ends checked for looseness before completing diagnosis?
Rack mounting bushings tight with no movement of rack under steering input?

EPS Calibration and Software

Many EPS issues require calibration or software updates rather than part replacement.

TSBs and software updates checked for EPS module on this specific vehicle?
Steering angle sensor calibrated per OEM procedure after any mechanical work?
EPS module reset or relearn procedure performed where available?
EPS warning light extinguished after calibration and code clearing?
Road test confirms normal steering assist feel at parking lot speeds and highway speeds?

Documentation and Customer Communication

Document EPS diagnosis and educate customer on EPS system characteristics.

Complete EPS diagnosis including all tests, codes, and calibrations documented on repair order?
Customer advised that EPS assist varies by design with vehicle speed (may feel heavy at highway)?
If thermal shutdown occurred: customer educated on avoiding rapid full-lock cycles to prevent recurrence?
Any required EPS module, rack, or sensor replacement quoted and approved before parts ordered?
Pre- and post-repair scan results archived for warranty and liability documentation?
Customer advised to return if warning light reappears or assist changes within 30 days?
EPS extended warranty or OEM coverage checked before billing customer for module replacement?
Final road test documented confirming normal steering assist at all speeds and conditions?

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Why Use This Electric Power Steering System Diagnosis Checklist?

This electric power steering system diagnosis checklist helps automotive service teams maintain compliance and operational excellence. Designed for ase a4-certified technician / eps specialist professionals, this checklist covers 28 critical inspection points across 5 sections. Recommended frequency: per steering complaint / per eps warning light.

Ensures compliance with ASE A4 Suspension and Steering Certification, FMVSS 203 and 204 (Steering Control), OEM EPS Calibration Procedures, SAE J3082 Electric Power Steering Standards, UK MOT Steering System Requirements, India CMVR AIS-034 Power Steering Requirements. Regulatory-aligned for audit readiness and inspection documentation.

Frequently Asked Questions

What does the Electric Power Steering System Diagnosis Checklist cover?

This checklist covers 28 inspection items across 5 sections: EPS Fault Code Retrieval and Initial Assessment, Torque Sensor and Column Inspection, Steering Rack and Column Mechanical Inspection, EPS Calibration and Software, Documentation and Customer Communication. It is designed for automotive service operations and compliance.

How often should this checklist be completed?

This checklist should be completed per steering complaint / per eps warning light. Each completion takes approximately 30-60 minutes.

Who should use this Electric Power Steering System Diagnosis Checklist?

This checklist is designed for ASE A4-Certified Technician / EPS Specialist professionals in the automotive service industry. It can be used for self-assessments, team audits, and regulatory compliance documentation.

Can I download this checklist as a PDF?

Yes, this checklist is available as a free PDF download. You can also use it digitally in the POPProbe mobile app for real-time data capture, photo documentation, and automatic reporting.