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v3hardreset

V3 Hard Reset

In some rare situations, it may be necessary to do a hard reset of your V3 flash device (reset back to original defaults). The following describes how to do that.

  1. Turn the ignition on (don't start the engine)
  2. Wait for the CEL light to go back off after a few seconds just as a check that the ECU is up and running normally.
  3. Press the throttle to the floor and keep it there as you cycle the ignition key off and then back on 3 or 4 times. I usually go for 4 but 3 is the minimum. Pause for just a moment between on/off switches (about a 0.5-second pause, but not more than 1.5 seconds).

Once you have done that, the ECU should reset back to the hard coded defaults in the chip.

Additional notes:

  1. The vehicle speed must be zero.
  2. ThrotPos must exceed 72%. (Verify by logging.)
  3. Beginning with the ignition on but the engine not running, the minimum sequence is: turn the key off (first time) for 1/2 second, on for 1/2 second, off (second time) for 1/2 second, on for 1/2 second, off (third time) for 1/2 second, then on and leave on. (The speed of the off-on should be about like a clock going tick-tock or a bit faster. Failure to reset usually is caused by toggling the key too slowly.)
  4. If you initiate logging prior to performing the reset sequence, the logging will halt (the seconds counter will stop updating) the instant the reset happens.
  5. With firmware v3.18.205 or earlier in the ECU, to be sure that the default settings are properly saved after executing the hard-boot procedure, use the PC app to modify any configuration value and Save to ECU before shutting off the ignition.
v3hardreset.txt · Last modified: 2009/07/24 14:56 by dmertz