L83 only starts on cam sensor
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Joined: Jul 2023
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L83 only starts on cam sensor 2017 Silverado 5.3. After replacing the engine will not start when crankshaft sensor is plugged in truck runs on only cam sensor but no rpm reading and runs decent enough. Code P0340 camshaft sensor circuit and P0335 crankshaft position sensor circuit (probably because it’s unplugged). Tested the wiring 5 volts to signal and ref wire and good ground wire at cam and crank plug in. Unplugged harness at ECM IGN ON and made sure they weren’t getting voltage from somewhere else and all wires had infinite resistance when unplugged at ECM with ign on meaning there should be no short to ground issues. Also heard for the most part the reading would be off from 5v if there was a wiring issues but tested to be safe. Figure wiring is good and ECM is good because those are the only 2 codes / problem (could be wrong). Tried with both brand new sensors and did the same thing ( when both are plugged in the truck fires up for 3 seconds then shuts off ). Took a video of the reluctor wheel while cranking over by hand and it looks good. What am I missing and what could I have done wrong? THANKS
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Joined: Aug 2010
Posts: 7,323
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From: Ann Arbor, MI
If you really do have the crankshaft sensor disconnected, you will have to give us an update when you figure all this out.
