Ground Circuits
WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 2003 Pontiac Grand Prix, 2003 Pontiac Bonneville, 2003 Chevrolet Monte Carlo, 2003 Chevrolet Impala, and 2003 Buick Regal. However, it is still accessible from the selected car via links, so may be relevant.
- Using DVOM, check for continuity to ground at PCM ground terminals. For connector terminal identification, see CONNECTOR IDENTIFICATION in SELF-DIAGNOSTICS - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article. See WIRING DIAGRAMS . Resistance should be less than 5 ohms. If resistance is not less than 5 ohms, repair open in ground circuit.
- Connect negative lead of DVOM to a known-good ground. Backprobe positive lead of voltmeter to each PCM ground terminal. With vehicle running, DVOM should indicate less than one volt. If DVOM reading is greater than one volt, check for open, short to voltage, corrosion or loose connection in ground circuit.