Replace the main relay (PGM-FI relay) in the under-hood fuse box to restore power to the fuel injection system and other critical vehicle systems.

Warnings

Tools required

Parts

• Main relay (PGM-FI relay) × 1 — Use OEM Honda part number 39794-TBA-A01 or equivalent

Preparation

1. Park vehicle on level ground and apply parking brake
2. Turn ignition to OFF position and remove key
3. Allow engine to cool if recently operated
4. Open hood and secure with prop rod
5. Locate the under-hood fuse/relay box on the driver's side near the firewall

Procedure

1. 1

   Disconnect battery negative terminal
   Using a 10mm socket, loosen the negative battery terminal bolt. Remove the negative cable from the battery post and secure it away from the battery to prevent accidental reconnection. Wait at least 3 minutes to allow electrical systems to discharge.
   Torque spec

   Battery Terminal Bolts6 Nm (4 lb-ft)
2. 2

   Open under-hood fuse/relay box
   Locate the under-hood fuse/relay box cover on the driver's side of the engine bay. Release the clips on both sides of the cover by pressing them inward and lift the cover straight up to remove. Set the cover aside in a clean location.
3. 3

   Locate main relay position
   Refer to the diagram on the underside of the fuse box cover or in the owner's manual to identify the main relay (PGM-FI relay) location. It is typically a larger relay positioned in the relay section of the box, often marked as 'MAIN' or 'PGM-FI' on the box itself.
4. 4

   Remove main relay
   Firmly grasp the main relay body and pull straight upward with steady pressure to remove it from its socket. The relay has multiple pins that insert into the fuse box. If difficult to remove, gently rock the relay side-to-side while pulling upward. Do not use excessive force or pry tools that could damage the socket.
5. 5

   Inspect relay socket
   Examine the relay socket in the fuse box for any signs of corrosion, melted terminals, or debris. If corrosion is present, clean contacts with electrical contact cleaner and allow to dry. Check for any bent pins that would prevent proper relay installation. If socket damage is found, the entire fuse box may require replacement.
6. 6

   Install new main relay
   Align the new main relay with the socket, ensuring the pins match the holes in the socket. The relay will only fit in one orientation. Press the relay firmly and evenly into the socket until it is fully seated and flush with surrounding relays. Verify that all pins are properly inserted and the relay is secure.
7. 7

   Reinstall fuse box cover
   Place the fuse box cover back onto the fuse/relay box, ensuring it is properly aligned with the mounting points. Press down firmly on both sides until the clips engage with an audible click. Verify the cover is secure and fully seated.
8. 8

   Reconnect battery negative terminal
   Place the negative battery cable back onto the negative battery post. Thread the terminal bolt by hand to ensure proper engagement, then tighten to specification using a torque wrench and 10mm socket. Do not overtighten as this can damage the battery post or terminal.
   ⚠Do not overtighten battery terminal bolts beyond specified torque as this can crack the battery post or strip the terminal threads.
   Torque spec

   Battery Terminal Bolts6 Nm (4 lb-ft)

Reassembly

1. Ensure fuse box cover is properly secured with all clips engaged
2. Verify battery terminal connection is tight and corrosion-free
3. Reset clock and radio presets as needed

Verification

• Turn ignition to ON position (do not start engine) and verify that dashboard lights illuminate normally
• Listen for the fuel pump priming (a brief whirring sound from rear of vehicle for 2-3 seconds)
• Start the engine and verify it starts normally without extended cranking
• Check that all electrical systems function properly (lights, accessories, gauges)
• Verify no warning lights remain illuminated on the dashboard after startup
• If engine does not start or fuel pump does not prime, recheck relay installation and socket condition

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