Key ON/Engine OFF Self-Test

There are 4 codes displayed during this test. The first is a Fast code, which is not applicable in field testing. Fast codes are represented by slight needle deflections on analog VOM. These are standard service codes being run at a rate too high for the testers to read. Fast codes are used by automatic equipment during manufacturing processes.

In order of display, the next 3 codes used for this test are the On Demand code, the Separator code, and the Continuous/Memory code. The first service code shown in this test sequence is the On Demand code. The On Demand code indicates a malfunction which is present at time of testing. This type of malfunction is called a "hard fault".

The second code is the Separator code, which indicates that On Demand codes have ended the Continuous/Memory codes are about to start. The third code is the Continuous/Memory code, which indicates a recent problem which is not present at time of test (intermittent fault).

The On Demand first digit is indicated by a pulse or pulses, after which the needle drops to zero (0) for 2 seconds before the second digit of the code is indicated as a pulse or pulses. After a pause of 6-9 seconds, the Separator code (single digit on VOM; 10 on STAR tester) will be displayed for 1/2 second. After 6-9 seconds, the first digit of the Continuous/Memory code will be indicated, the needle then dropping to zero (0) for 2 seconds, and then the second digit of the Continuous/Memory code will be indicated.