MFI Control Relay

1994 Hyundai Elantra GLS, StandardSECTION MFI Control Relay
  1. Remove control relay, located behind driver's dash panel next to hood release lever. Apply battery voltage across terminals No. 6 (positive) and No. 8 (negative) while checking voltage on terminals No. 1. See Fig 1 . Replace relay if battery voltage does not exist.
  2. Apply battery voltage across terminals No. 7 (positive) and No. 10 (negative) while checking continuity between terminals No. 3 and 4. Replace relay if continuity does not exist.
  3. Apply battery voltage across terminals No. 3 (positive) and No. 9 (negative) while checking voltage on terminal No. 4. Replace relay if battery voltage does not exist.
    Fig 1: Identifying Control Relay Terminals
    G93G80578Courtesy of HYUNDAI MOTOR CO.
  4. Disconnect ECM connector. Turn ignition on. Using DVOM, measure voltage between ECM harness connector terminal No. 6 (10-pin connector) (terminal No. 22 on Calif. Elantra - 22-pin connector), and vehicle ground. If voltage is less than battery voltage, inspect and repair circuit as needed.
  5. Disconnect control relay harness connector. Using DVOM, measure voltage between control relay harness connector terminal No. 6 (White/Blue wire) and vehicle ground. If voltage is less than battery voltage, inspect and repair circuit as needed.
  6. Turn ignition off. Using ohmmeter, check resistance between control relay harness connector terminal No. 8 (Brown/Red wire) and ECM harness connector terminals No. 12 and 15 (18-pin connector), (terminal No. 1 on Calif. Elantra) See Figure and Figure . If continuity does not exist, inspect and repair circuits as needed.
  7. Using ohmmeter, check resistance between control relay harness connector terminal No. 1 (Red wire) and ECM harness connector terminals No. 4 and 9 (10-pin connector) (terminals No. 2 and 5 on Calif. Elantra) See Figure and Figure . If continuity does not exist, inspect and repair circuits as needed.
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When to See a Mechanic

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

  • β€’ You smell fuel, burning insulation, or see smoke.
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