Run the diagnostic mode
by having the engine running and pressing AUTO and <=> (Vent)
at the same time. "0" should display in the ACC panel and will remain
there until the sequence is completed. If the previously selected
temperature returns to the display, the system has successfully
calibrated itself and found no faults. If a single digit number is
displayed, that is the number of faults in the
system.
Always check for power
and ground to the ACC unit. Never measure resistances with the ACC
control unit plugged in. Never unplug the ACC unit with the key on.
Make all measurements from the backside of the pin connectors to
prevent damage to the small pins. Make sure all connectors are clean
and fit together tightly. Look for pins that are pushed back in their
connectors. Read all procedures thoroughly and follow any warnings
they may give.