Engine Controls - Self-Diagnostics: Overview Mazda 626 GF

Description

KOEO on-demand self-test is a functional test of PCM performed with ignition key on, engine off. This test checks if PCM inputs and outputs are functioning electronically without any faults. A fault must be present at time of testing for KOEO on-demand self-test to detect a fault.

KOER on-demand self-test is a functional test of PCM performed with ignition key on, engine running. A check of certain inputs and outputs is made during operating conditions and normal operating temperature. The brake pedal position, transmission control and power steering switch tests are part of KOER on-demand self-test and must be performed during this operation (if applicable). A fault must be present at time of testing for KOER on-demand self-test to detect a fault.

Continuous memory self-test is a functional test of PCM performed under any condition (engine running or off) with ignition on. Unlike KOEO and KOER self-tests which can only be activated on demand, continuous monitor is always active in monitoring the system. When a fault is detected, DTC will be stored in memory. This makes it possible to diagnose intermittent faults.

There are 2 types of Continuous Memory DTCs. Emission related type DTCs will turn on the Malfunction Indicator Light (MIL) on instrument cluster. Non-emission type DTCs will never turn on MIL.

PID mode allows access to certain data values, analog and digital inputs and outputs, calculated values, and system status information. There are 2 types of PID lists available. The first is Generic OBD-II PID list. This is a standard set of PIDs that all scan tools can access. The second is a EEC-V specific PID list that can be accessed by using New Generation Star (NGS) scan tool. When accessing any PIDs from the specific PID list, the values are continuously updated.

HARDWARE LIMITED OPERATIONAL STRATEGY (HLOS)

If a number of system or sensor failures are present and PCM is not receiving enough information to operate, PCM will switch to HLOS mode. PCM will output fixed values to allow operation of vehicle. Driveability concerns will be present. PCM will not output diagnostic trouble codes in this mode.

OBD-II Drive Cycle Description

OBD-II drive cycle is a pattern of driving in which the PCM will execute all OBD-II diagnostic monitors. Drive cycle can be used to cause a DTC to set if a fault is present or to verify that a DTC will not return after a repair has been completed. If drive cycle is complete and P1000 is not cleared, repeat entire drive cycle.

Note. Rough road conditions may prevent certain steady state conditions and steady accelerations from validating the transmission and load related monitors.

DIAGNOSTIC TROUBLE CODE IDENTIFICATION TABLE

DIAGNOSTIC TROUBLE CODE IDENTIFICATON