Chevrolet Repair Questions? Ask a Chevy Mechanic for Answers ASAP
Did you torque the knock sensors to specification with a torque wrench?
Any new codes set in ECM?
Can you remove the small connector at the alternator and refit it a few times to see if this happens?
If it is the same code, then unlikely to be a faulty knock sensor.
A knock sensor (faulty or not) will not kill the battery.
Do you have a good battery to fit, and retest?
Sounds like you have an ECM fault if the harness and sensors are good.
Are prepared to swap the ECM?
I'll look up a circuit and come back to you shortly.
Strange, I have never seen the issue you have now.
Here is the circuit for the knock sensors.
What happens to the battery/charging voltage with the knock sensors disconnected?
Are they factory sensors?
Either you have a short within the harness, or the ECM is faulty.
One knock sensor is on C1/51, the generator field duty cycle is on C1/52.
Have you have replaced this harness all the way to the ECM connector?