2004 Chevy Pickup Engine Lamp On with DTC 332: No 5V Reference Signal from ECM

Hi everyone, I'm new to this forum and hoping for some help. I recently purchased a 2004 Chevrolet 4x4 pickup with around 130,000 miles. The engine light has been on, and I've received a knock sensor fault code. I replaced the intake manifold, both knock sensors, and the associated wiring harness—this was due to rust and corrosion. After clearing the codes, the check engine light returned within a few weeks. A scan tool revealed DTC 332 (Knock Sensor Circuit Malfunction). I disconnected the harness from each sensor and tested resistance: rear sensor reads 100.3 ohms, front sensor reads 04.2 ohms—both are within specification (93–107 ohms), so the sensors themselves appear functional. However, when the key is on, I'm not detecting any voltage at the harness side of the plug. According to the specifications, there should be a 5-volt reference signal from the ECM to the knock sensor. Is this expected? If so, which pin on the ECM connector provides this reference voltage? I don't have access to a service manual for my truck, so any guidance or wiring diagram references would be greatly appreciated. Thanks in advance for your help!