Diagnostic Aids

ECM/PCM applies and monitors a 5-volt DC signal to knock sensor. Internal knock sensor circuitry pulls this DC signal down to about 2.5 volts. When knock sensor detects detonation, it generates an AC signal which rides back on DC signal to ECM/PCM. Knock signal intensity is dependent upon knock signal level.

Fig 1: CODE 43, Schematic, ESC W/O Spark Control Module

Fig 2: CODE 43, Flowchart, ESC W/O Spark Control Module