1994 Hyundai Excel Base, StandardFACTORY OEM SERVICE PROCEDURE

MFI Control Relay

  1. Remove control relay, located behind glove box. Using an ohmmeter, check resistance between terminals No. 3 and 8 and then terminals No. 2 and 8. See Fig 1 . Resistance should be about 95 ohms. Check resistance between terminals No. 6 and 7. Resistance should be about 35 ohms. If resistance is not as specified, replace control relay. If resistance is as specified, go to next step.
  2. Connect a 12-volt battery across relay terminals No. 6 (positive) and No. 7 (negative). See Fig 1 . Continuity should exist between terminals No. 1 and 4. Disconnect battery voltage from relay. Using an ohmmeter, check for continuity between terminals No. 1 and 3. Continuity should not exist. Connect 12-volt battery across terminals No. 5 and 7. Continuity should exist between terminals No. 1 and 3.
  3. Disconnect battery voltage from relay. Check for continuity between terminals No. 7 and 5 and then reverse leads. Continuity should exist in one direction only. If results are not as specified, replace control relay.
    Fig 1: Identifying MFI Control Relay Terminals
    G93F80577Courtesy of HYUNDAI MOTOR CO.
  4. Check ignition switch supply voltage of control relay. Disconnect control relay connector. Turn ignition on. Using DVOM, measure voltage between terminal No. 5 (Black/White wire) of relay harness connector and vehicle ground. If voltage measured is not battery voltage, inspect and repair circuit between ignition switch and control relay.
  5. Check continuity of control relay ground circuit. Turn ignition off. Using ohmmeter, check continuity between control relay harness connector terminal No. 7 (Black wire) and vehicle ground. If continuity does not exist, inspect and repair circuit between control relay and vehicle ground.
  6. Check battery supply voltage of control relay. Using DVOM, measure voltage between terminal No. 1 (White/Blue wire) of relay harness connector and vehicle ground. If battery voltage is not present, inspect and repair circuit between battery and control relay.
  7. Check continuity of circuit between control relay and ECM. Disconnect ECM connector. Check continuity between control relay harness connector terminal No. 2 (Red wire) and ECM terminals No. 2and 15 of 26-pin connector. See Figure .
  8. If continuity exists, harness is okay. If continuity does not exist, inspect and repair circuits between control relay harness connector and ECM.
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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.

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