Hard Code

A diagnostic trouble code that comes back within one cycle of the ignition key is a "hard" code. This means that the defect is there every time the powertrain control module checks that circuit or function. Verify if the trouble code is a hard code at a the beginning of each test. When it is not a hard code, an "intermittent" test must be performed.

Codes that are for OBDII monitors will not set with just the ignition key on. Comparing these to non-emission codes, they will seem like an intermittent. These codes require a set of parameters to be performed (The DRBIII pre-test screens will help with this for MONITOR codes), this is called a "TRIP". All OBDII DTCs will be set after one or in some cases two trip failures, and the MIL will be turned on. These codes require three successful (no failures) TRIPS to extinguish the MIL, followed by 40 warm-up cycles to erase the code.