Diagnostic Aids

WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 1993 Pontiac Bonneville, 1993 Oldsmobile Ninety-Eight, 1993 Oldsmobile Eighty-Eight, 1993 Buick Riviera, and 1993 Buick Regal. However, it is still accessible from the selected car via links, so may be relevant.

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. Resistance to ground through knock sensor should be 3300-4500 ohms. Also check for proper installation of MEM-CAL.

Fig 1: Code 43 Schematic W/O ESC Module (All Models) ESC Error

Fig 2: Code 43 Flow Chart W/O ESC Module (All Models) ESC Error