2010 GMC Sierra 1500 - P0340 Intermittent Cranking and Stalling

Question

My truck is suddenly taking several seconds of cranking before it fires up, and it occasionally stalls out when I am coming to a stop. The check engine light is on and throwing code P0340 for the camshaft sensor. Sometimes it runs completely fine, but other times it feels like it has no power at all.

Kevin Tran · Accepted Answer

The issue turned out to be a combination of a cheap aftermarket sensor and a corroded connector pin. I replaced the pigtail with a genuine GM 13580874 connector and swapped the sensor for an AC Delco 12591290. Total cost for parts was about $85. Once the OEM sensor was installed and I cleared the codes, the truck started instantly and the P0340 has not returned in over 500 miles.

fleet_chief_42 · Answer

Are you using an AC Delco sensor? These GM engines are extremely picky about the signal frequency. Aftermarket sensors from brands like Duralast or BWD often fail right out of the box or produce a 'noisy' signal that the PCM doesn't like.

turbo_tony · Answer

Check the wiring harness near the back of the intake manifold. These LS engines are known for the cam sensor pigtail getting brittle from heat or being chewed by rodents, which causes a circuit malfunction signal even if the sensor is new.

Tom Patel · Answer

You should also check your battery voltage and starter draw. If the battery is weak or the starter is pulling too many amps, it can drop the system voltage enough during cranking to prevent the cam sensor from sending a clean signal to the PCM.

2010 GMC Sierra 1500 - P0340 Intermittent Cranking and Stalling

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