The first time we had a problem we had gone to the Dr.and when we came out to start the truck it started and ran for about 15 seconds then died. It would crank but not start. About an hour later after cranking for a few it started. we had a diagnostic done on it it threw a code for crankshaft positioning sensor. We replaced it with a Napa part. As soon as the temperature outside would get above 90 degrees it would quit again. Another diagnostic and the same code came up. so thinking we got a faulty part we had it changed again. Again as soon as it got hot outside it would quit.So we talked to our mechanic and he suggested we try a Delco part that GMC vehicles will only work with Delco parts. So we ordered one. They are on nationwide backorder, so I am assuming this a problem a lot of vehicles are having. What I dont understand is why it only has a problem when the weather gets over 90 degrees. And of course we live in the cenral valley of californa and it is extremly hot in the summer. Does any of this make sense to you? Any thoughts on this problem would be extremly helpful we are just lost at this point. This truck has been such a great vehicle. Oh and btw it only has 48000 miles on it.
Crankshaft Positioning Sensor on 2006 GMC Sierra 3500
by celbisi in Exeter, CA on August 12, 2012
1 answer 2 comments
ANSWER by globalhelper on August 12, 2012
when you repl crank sensor u must do a relearn on it or it won't function properly. did you have that done? but you are correct you should use delco part but try relearn brfore you condem senor
COMMENT by celbisi on August 12, 2012
Yes that was done for the Napa Parts......they seemed to work for a short time. It was almost like they just burnt out after so many starts. Im talking like maybe a dozen or less starts. Will have to wait on the delco part I guess. No telling when it will be here. Thank you for your help. Any ideas on the temperature (weather) issue?
COMMENT by Chevy Power on August 13, 2012
The crank sensors on that engine were very problematic. What was happening is the hole in top of the engine block that the sensor goes through, would rust and squeeze the sensor until it cracked. Once it cracked moisture would get in and short it out. I would recommend that whomever replaces the current sensor cleans all the rust out of the hole and applies an anti-seize lubricant to the sensor body.