I've been trying to track down this problem for months and have gotten no where. I'm getting a P0017 error. I've tested the crankshaft position sensor, both camshaft sensors and the VVT's. The crankshaft and camshaft sensors show 4.5 volts when key is in the on position. From what I've watched online it should be 12 volts, right? If that's the case then I'm not getting enough volts to all 3 sensors. I'm guessing though since all 3 show the same voltage that has to be accurate. Any help would be appreciated. Here's a freeze frame.

 

Should be 5V reference voltage assuming that's what you are testing. Several sensors share the 5V ref. from the PCM. One of these sensors may be faulty pulling the voltage down. A scope would be handy if you know how to use it. A wiring diagram is a must. You'll need to isolate the fault, unplugging sensors one at a time might turn up a faulty one. A competent diagnostic shop can run it down in under an hour. Good luck.

 

Thanks for the info. Spoke with a relative who's a GM mechanic and he said that there is a TSB for the 2.4L ecotec for the exhaust cam reluctor slipping off timing. The only fix is to replace it. Apparently it was common. Thanks again for the help.

 

A simple cam / crank correlation test using at least a 2 channel scope and a known good waveform could prove that in short order without replacing a single part. It also does not explain the lack of a 5V reference voltage on multiple sensors. Curious to see how you proceed. Good luck.