1979 Mazda RX-7 GS, Automatic TransFACTORY OEM SERVICE PROCEDURE

California Models

  1. Check condition of 5-amp fuse. Fuse is located on top of control unit. See Fig 1. Check that current flows to terminals "A" and "B" when engine is operating at idle speed (about 3-8 volts).
  2. Connect negative probe of voltmeter to terminal "P" and positive probe to other terminals under conditions described. Check that 12 volts exists at terminal "J" with decreasing engine speed less than 1150 RPM.
  3. Check that 12 volts exists at terminal "J" with engine operating and applying battery power (with jumper wire) to terminal "E" or "T". Check that 12 volts exists at terminal "L" with decreasing engine speed less than 1150 RPM.
  4. Check that 12 volts exists at terminal "M" or "Q" when applying battery power to terminal "S". Engine speed should increase less than 4600 RPM of idle within 130 seconds after engine start with choke knob fully out.
  5. Check that 12 volts exists at terminal "M" when applying battery power to terminal "E" and engine operating. Check that 12 volts exists at terminal "D" at any engine operating condition.
  6. Check that 12 volts exists at terminal "H" with engine speed increasing more than 4000 RPM of original speed. Check that 12 volts exists at terminal "R" while applying battery power to terminal "S" with engine speed increasing less than 3000 RPM of idle.
  7. Check that 12 volts exists at terminal "R" while applying battery power to terminal "S" at any engine speed within 130 seconds after starting engine with choke knob fully out.
  8. Check that 12 volts exists at terminal "G" with decreasing engine speed more than 1150 RPM above idle. On 1979 models, check that 12 volts exists at terminal "K" with engine operating and applying battery power to terminal "E" or "T".
Fig 1: Control Unit Terminal Identification (California Models
G09309993Courtesy of MAZDA MOTORS CORP.
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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.