LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Acura >> 1994 >> NSX Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Basic Diagnostic Procedures >> Fuel Systems >> Fuel Pump Control Circuit >> PGM-FI Main Relay
April 5, 2026: LEMON Manuals is launched! Read the announcement.

PGM-FI Main Relay

NOTE: If the car starts and continues to run, the main relay is OK.
  1. Remove the PGM-FI main relay.PGM-FI main relay is located behind passenger seat next to ECM. See Fig 1 .
    Fig 1: Locating PGM-FI Main Relay
    G00097615Courtesy of AMERICAN HONDA MOTOR CO., INC.
  2. Attach the battery positive terminal to the No. 4 terminal and the battery negative terminal to the No. 8 terminal of the main relay. Then check for continuity between the No. 5 terminal and No. 7 terminal of the main relay. See Fig 2 . If there is continuity, go on to next step. If there is no continuity, replace the relay and retest.
    Fig 2: Testing PGM-FI Main Relay
    G00107121Courtesy of AMERICAN HONDA MOTOR CO., INC.
  3. Attach the battery positive terminal to the No. 6 terminal and the battery negative terminal to the No. 2 terminal of the main relay. Then check that there is continuity between the No. 1 terminal and No. 3 terminal of the main relay. If there is continuity, go on to step. If there is no continuity, replace the relay and retest.
  4. Attach the battery positive terminal to the No. 3 terminal and battery negative terminal to the No. 8 terminal of the main relay. Then check that there is continuity between the No. 5 terminal and No. 7 terminal of the main relay.
  5. If there is no continuity, replace the relay and retest. If there is continuity, the relay is OK. If the fuel pump still does not work, check for intermittent failure. Check for poor connections or loose wires at the following connectors: C773 (fuel pump), C489 (located behind the seat back panels), C491 (fuel pump relay), C152 (fuel pump resistor), C481, C482 (PGM-FI main relay), C160, C161 (located behind the passenger's seat back panel) and ECM. For additional testing follow the flow charts. See Fig 3 and Fig 4 .
Fig 3: PGM-FI Main Relay Diagnostic Flow Chart (1 Of 2)
G00107122Courtesy of AMERICAN HONDA MOTOR CO., INC.
Fig 4: PGM-FI Main Relay Diagnostic Flow Chart (2 Of 2)
G00107123Courtesy of AMERICAN HONDA MOTOR CO., INC.
scientia non olet · About LEMON Manuals