Serial Data Communications

A "TRIP" is defined as a key On-Run-key Off cycle in which all the criteria were met for a given diagnostic test to run. During any given drive cycle key On-Run-key Off criteria may or may not have been met to perform all diagnostic tests. No "TRIP" will occur for a given diagnostic until the vehicle is driven in such a manner as to meet all the enable criteria. If a test is desired on a particular subsystem to determine if it "passes" or "fails" refer to the specific DTC for test parameters. The parameters are calibrated conditions the PCM requires in order to perform the test. If a test has not been run. monitor the Scan tool pass/fail DTC status at the time the parameters have been met.

Last Test: Failed - Indicates that the last time a diagnostic test was performed on a particular system or sub-system it failed. A problem may no longer exist. but since another test has not been run, the fault still appears failed. A failed status will remain between ignition cycles if a test was not run and did not pass prior to turning Off the ignition.

IMPORTANT: If a catalyst-damaging misfire occurs and a misfire DTC sets (type A), the MIL lamp will be turned Off after three passed trips.

MIL Requested - Indicates whether a diagnostic DTC trouble code is requesting the MIL to be illuminated.

It is important to remember that the DTC as well as any stored malfunction history will be erased if the vehicle battery has been disconnected or a clear DTC command is issued to the PCM. DTCs and malfunction history records will also be erased if 40 passes have been recorded without any faults. The emission DTCs (type A or B) will use a separate counter from the non-emission (type C and D) codes.

Warm Up Cycle
A warm-up cycle is defined as engine temperature reaching a minimum of 71°C (160°F) and a rise in temperature of at least 22°C (40°F) over the course of a trip.