Circuit Description

This diagnosis detects open circuit or short-circuiting in the Ignition Electronic Spark Timing (EST) line by monitoring EST signals. The independent power device (IPD) is built into the ECM. The IPD drive control IC has a diagnostic function that monitors power output circuit condition and sends the applicable data to the ECM where it is interpreted. If there is an abnormal indication or the circuit is open, the code data is stored in memory.