PCM Reset

1999 Mazda 626 ES, 2.5 D, StandardSECTION PCM Reset

After a PCM reset procedure has been performed, the following conditions will be met:

  • All DTCs will be cleared from PCM memory.
  • All freeze frame data will be cleared from PCM memory.
  • Diagnostic monitoring results will be cleared from PCM memory.
  • OBD-II system monitor status will reset.
  • DTC P1000 will be set in PCM memory until all OBD-II system monitors or components have been tested to satisfy OBD-II drive cycle without any faults occurring. To clear DTC P1000, perform OBD-II DRIVE CYCLE. See DRIVE CYCLESΒ  under ADDITIONAL SYSTEM FUNCTIONS.

To perform PCM reset using scan tool, follow scan tool manufacturer's operating instructions. If after clearing DTCs a problem has not been corrected or fault is still present, hard code will immediately be reset in PCM memory.

CAUTION: When battery is disconnected, vehicle computer may lose memory data. Driveability problems may exist until computer systems have completed a relearn cycle. See COMPUTER RELEARN PROCEDURES article in GENERAL INFORMATION before disconnecting the battery.
RENDER: 1.0x

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