AC DRIVE CONTROLLER ERROR CODE 39

The most common cause of error code 39 is when the ignition key is turned on 72VDC positive is sent to pin #1 of the AC drive speed controller located in the rear passenger's side inner panel. The controller starts up and performs its internal checks. If all is good, it will close the main contactor also referred to as coil. Contactor is located in the driver's side rear inner panel. This provides power to go to B+ on the controller which is the battery cable connection. When doing so the controller measures the voltage at pin#1 and B+ then compares them. If the voltage at B+ drops over 5 volts error code 39 is thrown and as a result main contactor is opened and vehicle will not operate. This can be due to a number of things.

1. First thing to note is when turning the key on and off do you hear the main contactor clicking in the back. You should hear a click then if error is presented there will be a second click which is the contactor re-opening. If you don't hear the click at all then you either have faulty wiring to the contactor or a faulty contactor itself. For more info testing this see this flow chart. Otherwise:

2. The main drive fuse is blown or has added resistance. Either fuse can be replaced to test this, or a simple test can be done by bypassing the fuse. Simplest approach would be to move the battery cable to the opposite end of the fuse basically eliminating the fuse. This would be just for testing purposes. After doing so turnkey back on and see if error code is gone. If so, fuse is bad, Replace the fuse. If not:

3.   A loose battery cable connection anywhere in the system can cause this. Corrosion on a battery post or so forth. Take and inspect each of the battery cable connections through out entire vehicle. If issue is found correct and retest by turning key on and seeing if error is gone. Otherwise:

4. The main battery disconnect switch in the right front wheel well could have a faulty internal connection. This can be either be replaced or tested by bypassing it. Then retest by turning key on and seeing if error is gone. Otherwise:

5. The main contactor could have a faulty internal connection replace and retest. Note the contactor cannot be bypassed in anyway. The controller will throw other codes if it is bypassed.