UrS4boy

Here are some photos of the G40 Cam Position Sender and its wiring:







If you are clever, you can set up an LED to show you that the CPS is working properly by connecting an LED between Pins 2/3 and 3/3, using instructions written by Marc S. at EFI Express


Photo courtesy of Marc S. at EFI Express

MORE G40 Cam Position Sensor (CPS) info

GoHeels

Good stuff Dave. Pretty much what I did a few months ago, with a $2 LED from Radio Shack.
For me, just inserting the wire into the harness allowed the S6 to start on occasion, so I could get home to change the CPS.

*ps - I was away for a week so... Happy Birthday

UrS4boy

Thanks (for the birthday wishes). As for the LED, I presume you followed Marc's instructions, i.e. long leg into the back of the middle (grey/red wire) pin and the shorter leg into the back of the brown ground wire pin?

Dave F.

UrS4boy

Interesting (or confusing). I just realized that I had a packet of Radio Shack (The Source in Canada) LEDs. So I went out the car and tried the trick. Didn't work. (car wouldn't start). So I removed the LED and tried starting the car. It started. Hmm....I left it running and inserted the LED legs into the same location and I got a glowing/blinking(ish) red LED. Okay. Shut off the engine and tried restarting. Nada. Crankety crank crank crank. Nothing. Remove the LED and tried again. Vroom. started right off. Hmmm...gonna email Marc.

Dave F.

GoHeels

Yeah, it was Marc's trick while I was waiting for the new CPS to arrive in the mail, and the longer leg went in the middle perhaps. I had cranked it a bunch, changed the fuel pump and cranked it more... all with no start. Then when I put the LED in to look for the "blink" it started, and I was able to drive it to the house and wait for the CPS.

UrS4boy

Marc replied and said:

""Hi Dave. you did it right. I should add a note that inserting the LED can at times cause a no start. The reason is because the cam sensor is a very weak signal. So weak that the resistance from the LED is enough to drag the output voltage down enough to not trigger the ecu.

This doesn't matter in the context of a car that isn't starting (why most people would be testing the cps in the first place). If you have somebody else crank the car over you'll note the LED is blinking, even if your car is now not starting. Incidentally, on vems, it always starts up with the led in place (stronger 5v supply)."