1986 Mazda 626 BaseFACTORY OEM SERVICE PROCEDURE

Code 8 (EGR Position Sensor - 626 Turbo)

  1. Check for poor connections at EGR position sensor connector. Repair or replace as necessary. If connections are okay, check resistance of EGR sensor. If resistance is incorrect, replace EGR position sensor.
  2. If resistance is correct, measure voltage at terminal "A" of EGR position sensor connector. If reading is between 4.5-5.5 volts, go to next step. If not, check for open or short circuit in wiring harness from terminal "A" of sensor to ECU connector.
  3. Measure voltage at terminal "2F" of ECU. If reading is more than 4.5 volts, check for open circuit in ground harness. Also check for open circuit in wiring harness from terminal "C" of sensor to terminal "2F" of ECU connector.
  4. If reading is zero volts, check for open circuit in wiring harness from terminal "C" of sensor to terminal "2F" of ECU connector. If reading is .23-1,1 volts, replace faulty ECU.
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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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