No 5 volt reference to ECT
 

2005 saturn ion no 5 volt reference to cts .help please

ECT= Engine Coolant Temp?

Engine temp sensor
 

Or coolant temp sensor no 5 volt reference only .45 volts when wire plugged in pcm. Unplugged I probed pcm 9 volts on pcm prong??????

2005 ion sedan 5speed

You have a partial short to ground either through another sensor or a rub through insulation on that circuit. You should never see 9 volts on the 5 volt circuit. You may have a damaged the pcm also. A factory service manual wiring schematic is the way to solve this. Maybe someone over at Saturnfans has seen this, it may be a common problem. There are many sensors that run on 5 volts. Is this the only problem and how did you locate it?
There may be more than one 5 volt driver in your pcm.