P1351 Fault Code on 2000 GMC 2500 4x4: IC Circuit High Voltage & Malfunction Diagnosis

Model: GM Fault Code: P1351 Posted: 2012-03-20 00:59

Hello everyone, I'm experiencing a serious issue with my 2000 GMC 2500 4x4 Crew Cab equipped with a 454 V8 engine. The vehicle is showing a diagnostic trouble code P1351: 'IC Circuit High Voltage' and 'IC Circuits 1 and 4 Malfunction'. The scan tool displays flashing codes — (O), (OH), and (E) — which indicates intermittent or persistent sensor issues. My truck turns over and fires up, but will not stay running. I've already replaced the fuel pump, filter, spark plugs, wires, cap, rotor, coil, coil modulator, camshaft position sensor, and two injectors. Despite these changes, the problem persists. My current suspicion is a faulty pre-converter sensor, but I'm not certain. Any insights or troubleshooting steps for this specific P1351 code on a 2000 GMC 25 or 4x4 would be greatly appreciated. Thanks in advance for your help! — Cody