KLR blink error codes How to extract diagnostic blink-codes using test socket (944Turbo only) BACKGROUND The KLR computer puts out a morse-code type blink signal at the test socket that may be used to diagnose problems with the wastegate-controlling cycling-valve, the knock-sensor operation, and throttle-position sensor. These are boost-related errors for the 944 Turbo cars only (because hey're the only ones with boost!). The test socket is located on the firewall just ahead of the fusebox. You can flip up the plastic cover plate and it should look like the picture to the right. Instead of buying the official Porsche diagnostic tool that plugs into this socket, you can use a simple LED to extract the blink codes. Use the two terminals labeled LED and + in the picture. The rotation of the socket may be different, so you can orient yourself by finding the C terminal that's off by itself. Connect the negative lead to the LED terminal, and the positive lead to the + terminal. The negative lead on the LED is the shorter one that's next to the flat spot on the casing. The positive lead is the longer one. VERIFYING CORRECT LED ORIENTATION You can check that you've got the LED hooked up right by disconnecting the throttle-position sensor with the car idling. If the LED goes on, then it's hooked up correctly. GETTING THE BLINK CODES Go out for a short drive and run it through the rev-ranges. Try small and full throtttle openings. Then bring it back and with the car idling, hook up the LED and check the blink-codes. If you have a problem that it knows about, you should get a group of blinks, a short pause and another group of blinks, then a long pause and the cycle repeats again. Or you may get more than one error code. For a listing of blink-codes and remedies, download this PDF-file Test-BlinkCodes.pdf.