Help us help you. By posting the year, make, model and engine near the beginning of your help request, followed by the symptoms (no start, high idle, misfire etc.) Along with any prevalent Diagnostic Trouble Codes, aka DTCs, other forum members will be able to help you get to a solution more quickly and easily!
Re:2011 traverse 3.6 gdi hard start/ no start issue.
hi guys i am looking for ideas where to go next. i dont have an expensive scanner so im trying to do this without. i have a 2011 traverse with the 3.6 gdi engine. the car came in with a hard start/no start issue. i can get the car running after long cranking but it wont keep running. it acts like the ignition is totally cutting out for a few milliseconds every few seconds. while this happens the tach is jumping and eventually i get a reduced power warning. i got a crank sensor code so i put in a brand new delco crank sensor. no change. all the wiring looks fine. i also got cam sensor codes so i tested them all plus the new crank sensor by back probing the signal wire with a multimeter and cranking over per dans video and the sensors seem to be switching off and on correctly. i used 2 different scanners on it and got differing codes. the first one i got:
p0341 camshaft position sensor
p0100 mas air flow
p0336 crankshaft position sensor
p0113 iat sensor
p0443 evaporative emissions
Hey vhehn! I see that all of the codes in that picture are indicated as Permanent. That doesn't necessarily mean those are current fault, just that they were stored at one point, and the PCM hasn't had enough time to recheck those systems. If you clear codes and recheck after a hard start, what do you get back as CURRENT?
GM PIP4914 might be a good explanation of your P0336:
Unfortunately, there's many different ways you can get a no start/hard start from these vehicles. :silly: Plugged catalytic converters and failed timing chains are the ones I see most often. The P0014 would support a possible chain problem. Failed high pressure fuel pumps happen, but usually the engine doesn't struggle to idle once the engine has started.
Are you able to monitor scan data during a hard start?
i have cleared several times and battery disconnect overnight. those codes keep coming back. i can monitor some data while cranking. didnt see anything unusual. thought about plugged cats but exhaust seems freely coming out tailpips.
As far as the codes coming back, they will keep coming back as "permanent" until the ECM is happy enough to think all is good. Even after you fix the problem, those dtcs will still be back as "permanent" and cannot be cleared. Only the ECM can clear them when it has confirmed the system has been repaired and has run its tests.
You want to clear them and see what shows in the tool as "current", to see what is going on right now to get some direction on where to go. Remember those "permanent" dtcs will still be there too, but focus on the "current" dtcs. Hopefully that helps.
i know these engines are terrible about timing chains but would that cause it to run and then start cutting out and die. trying to think through how that would manifest. with the tach cutting out at the same time as the engine ignition it lead me to think electrical.
