ACC II will allow the owner to run a calibration and diagnostic mode. However, it will not display the actual codes, just the number of them present. A little applied logic can pinpoint a course of diagnostic action however. The calibration should be carried out whenever a problem arises or the battery has been disconnected or discharged. Note all the symptoms you can when a problem arises and they will help you decide what could be the root of the problem. Distinguish if the problem only occurs in AUTO mode, but goes away when you select the settings manually. If the problems exist in both modes, suspect the problem to be either in the motors running the various flaps or mechanical in origin. If the problem exists in AUTO only, suspect a sensor problem. Suspect the ECU only when all other diagnostics show no problem.
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.
- ACC II Component Locations
- ACC II Wiring Diagram
- ACC II Wiring Component Locations
- ACC II Programming
- ACC II Limp Home Defaults (Use as starting point to determine a problem when output temperature is a problem)
- ACC II Power Checks
- ACC II Sensor Ground Faults
- ACC II Fan and Transistor Unit
- ACC II Sensors
- ACC II Motors
- ACC II Rear Door Fans
- ACC II Heated Rear Window and Mirrors
- ACC II Service Bulletins