LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Lexus >> 1991 >> LS 400 >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - System/Component Tests >> Relays >> EFI Main Relay
April 5, 2026: LEMON Manuals is launched! Read the announcement.

EFI Main Relay

NOTE: For more LS400 information, see ECU POWER SOURCE CIRCUIT diagnosis chart at end of article. Refer to CIRCUIT DIAGNOSIS CHARTS .
  1. EFI main relay is located in junction block No. 2. See Figure or Figure. Using an ohmmeter, check for continuity between relay terminals No. 1 and 3. See Figure-32. Ensure continuity is not present between terminals No. 2 and 4. If continuity is not as specified, replace relay.
  2. Apply battery voltage between relay terminals No. 1 and 3. Using an ohmmeter, check for continuity between terminals No. 2 and 4. If continuity is not as specified, replace relay.
scientia non olet · About LEMON Manuals