What do you mean by set off?. Do you mean they couldn't read it or couldn't get it to flash codes?. The process to reading codes on OBD 1 early systems is quite simple.
Turn ignition switch to OFF position
Locate Data Link Connector (DLC), see image below.
Jumper the A&B terminals(a paper clip or a jumper wire work ok)
Turn Ignition switch to ON position.
Count the flashes on the "
CHECK ENGINE" or "
SERVICE ENGINE" light.
FLASH, pause, FLASH, FLASH = code 12
