Diagnostic Aids

Check knock sensor signal circuit for a potential open or short to ground. An open knock signal circuit would cause 5-volt reference to remain high at PCM knock signal terminal. A short to ground in knock sensor signal circuit would cause 5-volt reference signal to pull low to near zero volts. If either of these conditions exists for about 10 seconds, a Code 43 will set. Resistance to ground through sensor should be 3300-4500 ohms.

Fig 1: Code 43 Schematic (Saturn) ESC Open Or Shorted

Fig 2: Code 43 Flow Chart (Saturn) ESC Open Or Shorted