2022-2024 Honda Civic EPS Gearbox Inspection TSB 23-089

Why This Matters: Honda Civic EPS Gearbox Defect

Honda has identified a manufacturing error affecting certain service part Electric Power Steering (EPS) gearbox assemblies in 2022-2024 Honda Civic vehicles. These gearboxes were not produced to the correct specifications, leading to an improper rack stroke. An incorrect rack stroke can result in noticeable changes to the vehicle's driving dynamics, potentially impacting steering feel and control. This issue with the Honda Civic EPS gearbox could affect the vehicle's handling and overall driving experience.

What's Being Addressed: Service Bulletin 23-089

Service Bulletin 23-089, Version 3, issued on December 10, 2024, supersedes the previous bulletin 23-089 dated December 8, 2023. This bulletin provides updated information regarding the inspection and potential replacement of the EPS gearbox. The campaign aims to correct the manufacturing defect by instructing technicians to inspect the EPS gearbox part number label. If the label indicates an affected part, the EPS gearbox will be replaced to restore proper steering function and maintain the intended driving dynamics of the Honda Civic.

Symptoms of an Affected Honda Civic EPS Gearbox

The primary symptom of this issue is a potential change in the vehicle's driving dynamics. Owners might notice differences in how the steering feels or responds due to the incorrect rack stroke in the Honda Civic EPS gearbox. While the bulletin does not specify particular warning lights or error messages, any unusual steering behavior should be investigated.

Important Warnings for Owners and Technicians

• Do Not Drive Advisory for Unsold Vehicles: Some vehicles affected by this campaign may be in new or used vehicle inventory. Honda states, "Repair these vehicles before they are sold." This implies that vehicles should not be delivered to customers until the update is completed.
• Steering Wheel Position: During the repair, technicians are explicitly warned: "Do not turn the steering wheel while disconnecting the steering joint."
• Power Tool Use: When installing the EPS motor/control unit, technicians must "DO NOT use power tools to install or tighten the bolts" to prevent damage to the motor and/or gearbox.

Parts and Tools Required

To perform the inspection and potential replacement of the EPS gearbox, specific parts and tools are required:

Parts Information

Part Name	Part Number	Quantity
Gearbox	53640-T21-316	1
Flange Bolt (12x75)	90161-SX8-T00	4
Washer Bolt (14X85)	90179-T20-A01	4
Flange Bolt (12x30)	90174-T20-A01	2
Washer Bolt (14X45)	90163-TGH-A01	2
Washer Bolt (14X85)	90130-T20-A00	1
Flange Bolt (14X35)	90181-TBA-A00	2
Flange Bolt (14X80)	90108-T20-A00	3
Split Pin (3.0X22)	94201-30220	2
Washer Bolt (10X25)	90159-TBA-A00	3
Self-Lock Nut (12mm)	90215-SB0-003	6
Flange Nut (10mm)	90002-S10-000	2

Tool Information

Tool Name	Part Number	Quantity
Subframe Adapter	VSB02C000016	1
Ball Joint Thread Protector (12mm)	07AAF-SDAA100	1
Ball Joint Remover (28mm)	07MAC-SL00202	1
Subframe Alignment Pin	070AG-SJAA10S	1

Inspection Procedure

The inspection involves several steps to determine if the EPS gearbox needs replacement:

1. Allow the engine to cool down.
2. Locate the parts label on the EPS gearbox.
3. Inspect the ID and part number on the label. If the ID is "WA" with P/N 53640-T21-3050-M1 or "WB" with P/N 53640-T21-3060-M1, a picture of the label must be taken and attached to the warranty claim. Then, proceed to the repair procedure.
4. If the EPS gearbox has any other ID or part number, no replacement is needed. A picture of the label should still be taken and attached to the warranty claim, but no further action is required.

Repair Procedure Summary

If a replacement is necessary, the repair involves a detailed process to remove and install the EPS gearbox. This includes:

1. Disconnecting the 12-volt battery terminals.
2. Disconnecting the steering joint, ensuring the steering wheel is straight and not turned during this step.
3. Raising the vehicle, removing front wheels (torqued to 80 lb-ft), engine undercover, and EPS harness connectors.
4. Removing the rubber exhaust mount (nuts torqued to 12 lb-ft).
5. Disconnecting stabilizer links (flange nuts torqued to 47 lb-ft) and front lower assembly bolts (torqued to 77 lb-ft).
6. Loosening outer tie-rod end nuts (torqued to 44 lb-ft) and disconnecting tie-rod end ball joints.
7. Disconnecting front lower arms (flange nuts torqued to 47 lb-ft).
8. Removing the engine torque rod front bolt (torqued to 70 lb-ft).
9. Attaching a subframe adapter (P/N VSB02C000016) and raising the transmission jack to remove the front subframe.
10. Transferring tie-rod ends and the steering shaft boot to the new gearbox.
11. Separating the EPS motor/control unit from the old gearbox and retaining it for the new one. This involves discarding the motor bush and O-ring.
12. Installing a new O-ring (supplied with the new gearbox) to the EPS motor/control unit, applying steering grease.
13. Installing the EPS motor/control unit onto the replacement rack, ensuring the barcode faces up. The unit must be turned two or three times to both the left and right in a 45° arc to seat it properly.
14. Loosely installing the EPS motor/control unit mounting bolts by hand, then torquing them to 20 N·m (15 lb-ft).
15. Installing the EPS gearbox to the subframe, torquing bolts as specified (9.5 N·m / 7.0 lb-ft, 44 N·m / 32 lb-ft, 92 N·m / 68 lb-ft).
16. Raising the subframe with alignment pins, installing mounting bolts, and torquing them to specification (103 N·m / 76 lb-ft, 95 N·m / 70 lb-ft, 93 N·m / 69 lb-ft).
17. Installing the pinion shaft to the steering joint and torquing to 29 N·m (21 lb-ft).
18. Connecting the 12-volt battery terminals (torqued to 4.4 N·m / 3.2 lb-ft).
19. Reinstalling remaining parts in reverse order.

Post-Repair Calibration

After the physical replacement, several calibration steps are required:

1. Center the steering wheel and ensure turning revolutions are equal from center to full lock.
2. Check for noise or abnormality by turning the steering wheel fully left and right with the tires raised.
3. Confirm the EPS provides power assist and that the "EPS indicator does not come on."
4. Perform a wheel alignment.
5. Perform the VSA Sensor Neutral Position Memorization using the i-HDS diagnostic tool. This involves parking the vehicle on a flat surface, connecting i-HDS, turning the vehicle to ON mode (engine off), setting the steering wheel straight, and selecting "ADJUSTMENT" from the "ABS/TCS/VSA" menu, then "ALL SENSOR."

Warranty Claim Information

For warranty claims related to this service bulletin 23-089, technicians must attach a photo of the EPS gearbox label to the warranty claim form. The EPS serial number must also be entered into the Test Code field (03214).

• Operation Number 5135D9 (Inspection):

  • Description: Inspect the parts label (includes photos)
  • Flat Rate Time: 0.3 hr
  • Defect Code: 6GT00
  • Symptom Code: DG400
  • Template ID: A23089A
  • Failed Part Number: 53640-T21-306

• Operation Number 5131M3 (Replacement):

  • Description: Replace the EPS gearbox (includes inspection, VSA relearn, and alignment)
  • Flat Rate Time: 2.0 hr
  • Defect Code: 6GT00
  • Symptom Code: DG400
  • Template ID: A23089B
  • Failed Part Number: 53640-T21-306

Important Note: When performing service bulletin 23-089 using the 53640-T21-316 parts, this will also satisfy the repair for service bulletin 24-119. To close the status of 24-119, a Campaign Status Change Request Form, along with a copy of the repair order, must be submitted to [email protected]. Claims for inappropriate replacements may be subject to debit.

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Source: NHTSA ID: 10254131