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 ECM knock signal terminal. A short to ground in knock signal circuit would cause 5-volt reference signal to pull low to near zero volts. If either of these conditions exist for about 10 seconds, a Code 43 will set. Resistance to ground through knock sensor should be 3300-4500 ohms.