05 astro cps problem

have an 05 astro that after i shut it off when it was hot wouldn't stay running. i scanned it and it came up with a cps (crank position sensor)code....p0335 i think. i replaced the cps and took it for a ride, ran great. stopped at an convienance store for a soda and when i came out it wouldn't run again. got the scanner and it threw out the same cps code. knowing the the cps was probably ok i went out and got another one anyhow. put it in...about an hour had gone by.. and she started right up and ran great. drove it around close to home for a while to make sure everything got good and hot. it still ran great, went home and shut it off, went into the house to take care of business and came out 5 minutes later and here we go again....won't stay running and is showing the same code for the cps. ok, so where do i go from here..........i'm gonna try to find the ecm and make sure the connections are ok there, the harness at the cps is fine. side note: i've had this van since new with no problems to speak of and it has 220,000 miles and is well taken care of. :runaround:
thanks Joe

When the problem is ongoing, check ref voltage-- signal and ground for the crank sensor.

If it cranks good but won't start, have a helper crank, check for spark at the plugs, anything?

ok, when it cools down it runs good again. will get it hot again and then check for voltage at the cps. read up on how to check the ground and the sensor signal to the ecm. i'll have a wiring diagram in the am so i can see where to check the signal at the ecm.........when it's hot it starts but pops and carries on so it's gettin some type of intermitant signal, just not enough for it to run right.

P0335 is in fact a circuit problem with the CKP sensor, not necessarily the sensor itself. As jdl mentioned, check the circuits and repair the wiring problem. Keep in mind that whenever the crankshaft position sensor is disturbed in any way, including moving, removing or replacing the sensor or the timing cover, a crankshaft position sensor relearn MUST be performed with a capable scan tool. If the relearn is not performed, the ECM will use the data from the last relearn which will be incorrect data, guaranteed. The engine will run with the old data, but not properly. Ignition timing, misfire data and injector timing will all be affected by the incorrect data.

P0335 is in fact a circuit problem with the CKP sensor, not necessarily the sensor itself. As jdl mentioned, check the circuits and repair the wiring problem. Keep in mind that whenever the crankshaft position sensor is disturbed in any way, including moving, removing or replacing the sensor or the timing cover, a crankshaft position sensor relearn MUST be performed with a capable scan tool. If the relearn is not performed, the ECM will use the data from the last relearn which will be incorrect data, guaranteed. The engine will run with the old data, but not properly. Ignition timing, misfire data and injector timing will all be affected by the incorrect data.

i'll check on that......however the vehicle runs great up until everything reaches the proper operating temp....appx 6 or 7 miles. then it starts running rough then quits. once it cools down.....2 or 3 hours you go through the whole process again. 2 days before all this started the ignition module went bad, i replaced that and it ran fine till all this started to happen......i'm kinda wondering if the new ign module might be shorting out when it gets hot, since that was the last thing that was touched...........soon as i get a few minutes i'll let it get hot and start testing.
thanks
joe

If the P0335 is still being set after clearing the memory, troubleshoot and repair that first. That might be the whole problem.