ACC II Troubleshooting
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.


 

 

Return To Climate Control Index

Return To Technical Document Index