2015 GMC Sierra 1500 - Random Stalling and P0340 Code

Question

My truck is intermittently stalling while coming to a stop and has a long crank time when trying to restart. Yesterday the Check Engine Light popped on and stayed on while I was on the highway. I hooked up my scanner and it pulled a P0340 code for the camshaft position sensor circuit.

Dave Kowalski · Accepted Answer

The issue was a combination of a faulty sensor and a slightly backed-out pin in the harness connector. I replaced the Camshaft Position Sensor with a genuine GM part number 12622236 ($55.00) and used a terminal tool to reseat the wires in the plug. After clearing the codes and performing a crank/cam variation relearn with my scan tool, the truck starts instantly and the stalling has completely stopped.

Pete Sanders · Answer

Before you replace the sensor, check the wiring harness behind the intake manifold. These often rub against the fuel rail or the back of the block, which can cause intermittent shorts in the 5V reference circuit.

hd_trucker_77 · Answer

Check your ground straps. A bad engine-to-chassis ground can cause enough electrical noise to interfere with the CMP signal. Try a voltage drop test between the battery negative and the engine block while cranking.

Rachel Nguyen · Answer

Are you hearing any lifter tick? Sometimes a mechanical timing issue or a failing phaser can mimic a sensor circuit code if the camshaft timing isn't lining up with the crankshaft position signal during startup.

2015 GMC Sierra 1500 - Random Stalling and P0340 Code

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