This procedure covers the removal and replacement of the ABS hydraulic unit (ABS pump/modulator assembly) on a 2018-2024 Honda Accord with the 1.5L turbocharged engine, including brake line disconnection, bleeding, and system verification.

Warnings

Tools required

Parts

• ABS modulator control unit assembly × 1 — Use OEM Honda part number for year-specific match
• Brake line sealing washers × 1 — Honda OEM brake line washers (typically 4 required)
• ABS unit mounting bolts (if damaged) × 1 — Use OEM specification

Fluids

• DOT 3 Brake Fluid — 1.5 qt

Preparation

1. Park vehicle on level surface and engage parking brake
2. Ensure ignition is off and wait at least 5 minutes before beginning work
3. Disconnect negative battery cable and wait 3 minutes for airbag system discharge
4. Remove engine cover if equipped by pulling upward on retaining clips
5. Place protective covers over fenders and painted surfaces near work area
6. Locate ABS modulator unit in engine compartment (driver side, near brake master cylinder and firewall)
7. Have drain pan and shop rags ready to catch brake fluid spills

Procedure

1. 1

   Relieve brake system pressure
   With the ignition off and battery disconnected, pump the brake pedal approximately 20 times until pedal feels firm and no vacuum assist remains. This depletes residual pressure in the ABS accumulator and brake booster.
2. 2

   Remove reservoir cap and extract fluid
   Remove the brake fluid reservoir cap. Using a turkey baster or fluid extraction pump, remove as much brake fluid as possible from the reservoir to minimize spillage during line disconnection. Dispose of old brake fluid properly.
3. 3

   Disconnect brake lines from ABS unit
   Using the appropriate flare nut wrenches, carefully loosen and disconnect the four brake lines from the ABS modulator assembly. There are two inlet lines from the master cylinder and two outlet lines to the front and rear brake circuits. Work slowly to avoid stripping the fittings. Immediately cap or plug the open lines to prevent fluid loss and contamination. Note the position of each line for correct reinstallation.
   ⚠Use only flare nut wrenches to prevent rounding off the brake line fittings. Standard open-end wrenches will likely damage the soft brass fittings.
4. 4

   Disconnect electrical connectors
   Locate the two electrical connectors on the ABS modulator unit. Press the locking tabs and carefully disconnect both connectors: the large main connector with multiple pins for the solenoid valves, and the smaller connector for the pump motor. Move connectors away from work area.
5. 5

   Remove ABS unit mounting bolts
   Remove the mounting bolts securing the ABS modulator assembly to its bracket on the firewall. There are typically 3-4 mounting bolts accessible from above. Support the unit with one hand as you remove the final bolt.
   Torque spec

   Mounting Bolts26 Nm (19 lb-ft)
6. 6

   Remove ABS modulator assembly
   Carefully lift the ABS modulator assembly up and out of the engine compartment. Be mindful of residual brake fluid that will drain from the unit. Have a drain pan positioned to catch fluid. Inspect the mounting bracket and area for corrosion or damage.
7. 7

   Prepare new ABS unit
   Unpack the new ABS modulator assembly and verify it matches the original unit exactly. Check that all port sizes and electrical connector configurations match. Install new sealing washers on all four brake line ports. Do not reuse old washers as they will not seal properly.
8. 8

   Install new ABS modulator
   Position the new ABS modulator assembly onto the mounting bracket, aligning it with the mounting holes. Install the mounting bolts hand-tight initially to ensure proper alignment. Once all bolts are started, torque them to specification in a cross pattern.
   Torque spec

   Mounting Bolts26 Nm (19 lb-ft)
9. 9

   Reconnect brake lines
   Reconnect the four brake lines to the new ABS unit in their correct positions (refer to notes from removal). Start each fitting by hand to prevent cross-threading. Once hand-tight, use flare nut wrenches to snug the fittings. Do not overtighten as this can damage the sealing washers. Typical specification is 14-16 Nm, but use tactile feedback - tighten until snug plus 1/4 turn.
   ⚠Cross-threading brake line fittings will ruin the new ABS unit. Always start fittings by hand and ensure they thread smoothly before using wrenches.
10. 10

    Reconnect electrical connectors
    Reconnect both electrical connectors to the ABS modulator, ensuring they click securely into place. Verify the locking tabs are fully engaged on both connectors. Check that no wiring is pinched or stretched.
11. 11

    Fill brake fluid reservoir
    Fill the brake fluid reservoir with fresh DOT 3 brake fluid to the MAX line. Keep the reservoir topped off throughout the bleeding process. Use only new, unopened brake fluid as moisture contamination will compromise ABS performance.
12. 12

    Perform manual brake bleeding
    Reconnect the battery. Perform conventional brake bleeding at all four wheels in this order: right rear, left rear, right front, left front. At each wheel, attach a clear hose to the bleeder screw, submerge the other end in clean brake fluid, open the bleeder, have an assistant slowly depress the brake pedal, close the bleeder before pedal reaches bottom, and release pedal. Repeat until fluid runs clear with no air bubbles. Keep reservoir filled throughout.
    ⚠Never allow the brake fluid reservoir to run empty during bleeding or air will enter the ABS pump, requiring extensive additional bleeding.
    Torque spec

    Bleeder Screw10 Nm (7 lb-ft)
13. 13

    Perform ABS system bleeding with scan tool
    Connect the Honda Diagnostic System (HDS) or equivalent scan tool capable of ABS functions. Navigate to the ABS bleeding function. Follow the scan tool prompts to activate the ABS pump and cycle all solenoid valves. This purges air from internal passages that cannot be reached by manual bleeding. The tool will cycle the pump in specific sequences while you monitor for fluid flow at the bleeders. This process typically takes 15-20 minutes and may require repeating the manual bleeding sequence afterward.
    ℹ️This step is absolutely critical. The ABS modulator contains internal valves and chambers that trap air unless cycled with a scan tool. Skipping this step will result in a soft brake pedal and potential ABS malfunction.
14. 14

    Final brake pedal test and top-off
    With bleeding complete, pump the brake pedal multiple times. It should feel firm and consistent with no sponginess. If pedal is soft, repeat bleeding procedures. Top off the brake fluid reservoir to the MAX line and reinstall the cap. Check all brake line connections for any signs of leakage.
15. 15

    Clear diagnostic codes and test system
    Using the scan tool, clear any ABS diagnostic trouble codes stored during the repair. Turn the ignition on (engine off) and verify the ABS warning light illuminates briefly then extinguishes. If the ABS light remains on, retrieve codes and address any issues before driving. Reinstall engine cover if equipped.

Reassembly

1. Verify all brake line connections are tight and show no signs of leakage
2. Ensure both electrical connectors are fully seated with locking tabs engaged
3. Confirm brake fluid reservoir is filled to MAX line with cap installed
4. Double-check that all mounting bolts are torqued to specification
5. Verify no tools or rags have been left in the engine compartment

Verification

• Start the engine and verify the ABS warning light extinguishes within a few seconds
• Pump the brake pedal with engine running - it should feel firm with normal travel and no sponginess
• Perform a low-speed test drive in a safe area, testing brake function at various pressures
• Perform an ABS activation test at low speed (15-20 mph) on a safe surface to confirm the system cycles properly
• Recheck all brake line connections for leaks after test drive
• Use scan tool to verify no ABS diagnostic codes are present
• Check brake fluid level after test drive and top off if needed

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