Electric Power Steering Module

This procedure covers the removal and replacement of the Electric Power Steering (EPS) module on the 2023 Chevrolet Bolt EUV, which controls steering assist without hydraulic fluid.

Warnings

Tools required

Parts

• Electric Power Steering Module × 1 — Use OEM specification
• Steering coupling bolt × 1 — GM 11609987 or equivalent
• Anti-seize compound × 1 — Use OEM specification

Preparation

1. Park vehicle on level ground and engage parking brake
2. Turn ignition off and remove key/fob from vehicle interior
3. Disconnect negative terminal of 12V battery (located in rear cargo area under floor panel)
4. Wait minimum 2 minutes for system capacitors to discharge
5. Remove lower steering column trim panels to access intermediate shaft
6. Center steering wheel and verify front wheels are pointing straight ahead
7. Mark relationship between intermediate shaft and steering column shaft with paint pen for reference

Procedure

1. 1

   Access the intermediate steering shaft coupling
   Remove the lower steering column covers by releasing the retaining clips. Locate the intermediate shaft coupling bolt where the steering shaft connects to the EPS input shaft. Use a paint marker to mark the alignment of the coupling before disassembly.
2. 2

   Disconnect intermediate shaft from EPS module
   Remove the coupling bolt connecting the intermediate steering shaft to the EPS module input shaft. Carefully separate the shafts, noting the alignment marks. Support the intermediate shaft to prevent it from hanging on the column.
   ⚠Do not rotate the steering wheel once the shaft is disconnected. This can damage the clockspring and require additional repairs.
   Torque spec

   Coupling Bolt34 Nm (25 lb-ft)
3. 3

   Disconnect electrical connectors
   Locate the main EPS module electrical connector on the module housing. Press the locking tab and carefully disconnect the connector. Inspect connector terminals for corrosion or damage. If a secondary connector is present, disconnect it as well.
4. 4

   Remove EPS module mounting bolts
   Locate the mounting bolts securing the EPS module to the firewall or subframe. There are typically 3-4 bolts. Remove all mounting bolts while supporting the module weight. Note the location of any ground straps or brackets that must be reinstalled.
   ⚠The EPS module weighs approximately 15-20 lbs. Support the module when removing the final mounting bolt to prevent it from falling.
   Torque spec

   Mounting Bolts27 Nm (20 lb-ft)
5. 5

   Remove EPS module from vehicle
   Carefully maneuver the EPS module out of the mounting area. It may be necessary to rotate or angle the module to clear surrounding components. Inspect the mounting area for corrosion, debris, or damage before installing the new module.
6. 6

   Prepare new EPS module for installation
   Remove the new EPS module from packaging and verify it matches the part number of the removed module. Inspect the input shaft splines and apply a light coat of anti-seize compound. Verify all mounting brackets and hardware are positioned correctly on the new module.
7. 7

   Install new EPS module
   Position the new EPS module into the mounting location, aligning it with the mounting holes. Insert all mounting bolts finger-tight first to ensure proper alignment. Once all bolts are started, torque mounting bolts to specification in a cross pattern.
   Torque spec

   Mounting Bolts27 Nm (20 lb-ft)
8. 8

   Reconnect electrical connectors
   Connect the main electrical connector to the EPS module, ensuring it clicks securely into place. Verify the locking tab is fully engaged. Connect any secondary connectors if present. Inspect all connections for proper seating.
9. 9

   Reconnect intermediate steering shaft
   Align the intermediate steering shaft with the EPS module input shaft using the alignment marks made during disassembly. Ensure splines are fully engaged. Install a new coupling bolt and torque to specification. Verify shaft connection is secure with no axial play.
   ⚠Always use a new coupling bolt. This is a critical safety fastener and must be torqued to exact specification.
   Torque spec

   Coupling Bolt34 Nm (25 lb-ft)
10. 10

    Reinstall steering column trim panels
    Reinstall the lower steering column trim panels, ensuring all retaining clips are fully engaged. Verify no wiring is pinched and that the column covers are secure. Check that the steering shaft boot is properly seated.
11. 11

    Reconnect 12V battery and perform system initialization
    Reconnect the negative terminal of the 12V battery. Turn the ignition to ON position (do not start vehicle yet). Allow the vehicle systems to initialize for 30 seconds. Check for warning lights on the instrument cluster, particularly the power steering warning light.
12. 12

    Calibrate steering angle sensor
    Connect a GM-compatible scan tool to the OBD-II port. Navigate to the steering angle sensor calibration procedure. Follow the on-screen prompts to calibrate the sensor with wheels straight ahead. This typically involves cycling the ignition and confirming wheel position. Clear any diagnostic trouble codes after calibration is complete.
    ⚠Failure to calibrate the steering angle sensor will result in stability control malfunctions and potentially dangerous vehicle behavior.

Reassembly

1. Verify all electrical connectors are fully seated and locked
2. Confirm all fasteners have been torqued to specification
3. Ensure no tools or parts were left in the steering column area
4. Check that steering wheel is centered and front wheels point straight ahead before test drive

Verification

• Start the vehicle and verify the power steering warning light extinguishes after initialization
• Turn the steering wheel lock-to-lock while stationary and verify smooth operation with no binding or unusual noises
• Use scan tool to verify no active DTCs related to steering system
• Perform a slow-speed test drive in a safe area, checking for normal steering assist and proper self-centering
• Verify stability control and lane keeping systems function normally without warning lights
• Road test at various speeds to confirm steering feel is consistent and vehicle tracks straight with hands off wheel briefly

Related trouble codes on this vehicle

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