Code 43 (1.6L Turbo) - ESC (Electronic Spark Control): Notes

ECM applies and monitors a 5-volt DC signal to the 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 the DC signal to the ECM. Knock signal intensity is dependent upon knock signal level.

1. Code 43 will set when vehicle reaches normal operating temperature (but not overheating) and the following conditions are present for 5 seconds:
   • High engine load is indicated by MAP sensor and engine speed.
   • A knock signal is indicated for more than 3 seconds.
   • MAT temperature is greater than 32°F (0°C).

   If an audible knock is heard from engine, repair mechanical problem first.

2. If tapping on engine lift hook does not produce a knock signal, try tapping on engine closer to sensor before proceeding.
3. This step determines the state of the 5-volt reference signal applied to the sensor.
4. Determines if fault is in knock sensor or ESC portion of MEM-CAL.