The owner had already replaced the alternator and multiple sensors. After hours of chasing wires, I checked the ECM power and ground feeds—they were perfect. On a hunch, I connected my scope to the 5-volt reference circuit.
Programmed 2008 Avalanche 1500 ECM 12612384 | Engine Control Module
1999-2000 Sierra 1500 PCM 09354896 Programmed to Your VIN
2002 GMC SIERRA 1500 BODY CONTROL MODULE BCM PROGRAMMED TO YOUR VIN 15063578
Programmed 2010-2012 Sierra 1500 Fuel Pump Control Module | 20791901
Programmed 2008-2012 Express 1500 BCM 15828601 | VIN Matched & Ready
Radiator Compatible with 2007-2013 Chevy Avalanche Tahoe Silverado 1500/2500/3500 Suburban 1500 Pickup & 2008-2013 GMC Sierra 1500/2500/3500 Yukon XL, 2 Row Full Aluminium Cooling Radiator
