1991 Mazda 929 SFACTORY OEM SERVICE PROCEDURE

Transfer Pump Control Unit (Protege 4WD)

  1. Turn ignition on. Ensure fuel gauge reads more than half full and transfer pump operation is heard. Ground transfer pump connector Yellow/Blue wire, and verify pump stops. Remove the ground from terminal Yellow/Blue wire, and verify pump operates after about 10 seconds. If pump does not operate as specified, see TRANSFER PUMP. See Fig 1 .
    Fig 1: Testing Transfer Pump Control System
    G90I04380Courtesy of MAZDA MOTORS CORP.
  2. Turn ignition on. Ground fuel pump control unit terminal "M" with jumper wire. Verify that zero volts is present at control unit terminal "N". Remove the jumper wire and check that voltage is 12 volts in about 10 seconds. If voltage is not as specified, disconnect transfer pump connector. Turn ignition on. Verify that the voltage is 12 volts at terminal "N" of the transfer pump connector. If not, replace transfer pump control unit.
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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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