P0335

P0335 means the ECM is seeing zero signal from the primary crankshaft position sensor circuit, which is the master timing reference for fuel and spark. A no-CKP-signal condition will throw a crank-no-start or a stumble-and-die, and on most platforms the engine will not relearn timing until the signal returns. Cheapest-first ladder: wiggle the CKP harness at the sensor connector and along the loom near the bellhousing while monitoring CKP RPM PID on a scan tool during cranking (should read 180-250 RPM steady; flatlining at 0 during wiggle = harness fault, not sensor). Pull the sensor and inspect the tip for ferrous swarf clinging to the magnetic pickup, which indicates worn bearings or a chewed reluctor and not a sensor problem at all. Bench-ohm the sensor cold (most variable-reluctance CKPs read 200-1000 ohms across the two signal pins; Hall-effect 3-wire types should pass 5V reference and ground continuity to ECM). Scope the signal during cranking and look for clean square waves (Hall) or sine waves (VR) with no missing teeth at the index gap. The expensive misdiagnosis here is throwing a $400 sensor and a tow bill at what turns out to be a chafed harness ground at the bellhousing bolt or a reluctor ring shifted on a slipped harmonic balancer.

Vehicle-specific patterns: GM 3.6L LY7 (2007-2012 CTS, Acadia, Enclave, Traverse) throws P0335 as a downstream symptom of timing chain and cam-actuator wear — the cam phasers wear oblong, the chain stretches, the CKP correlation goes out of spec, and you chase the crank sensor when the real fix is a full timing kit. Nissan VQ35DE (2002-2008 Altima, Maxima, 350Z) suffers CKP heat-soak failure where the sensor reads fine cold but drops out after 20 minutes at operating temp because it sits in exhaust heat near the bellhousing. Ford 5.4L 3V Triton (2004-2010 F-150, Expedition) sets P0335 as collateral damage when a failed cam phaser corrupts the crank correlation calculation — listen for the cold-start phaser rattle before condemning the CKP. Toyota 2GR-FE (Camry, Avalon, Sienna 2005-2012) goes intermittent above 4500 RPM as the sensor pickup ages and the signal amplitude drops below the ECM detection threshold. Estimated repair: $120 to $850 (sensor and labor on the cheap end, full timing job on the GM and Ford).