P1336

P1336 indicates a Crankshaft Position Sensor / Camshaft Position Sensor correlation fault — the PCM compares cam pulse-to-crank pulse phasing against a learned table and the relationship has drifted outside spec, typically more than 6 degrees of error. On Ford Modular engines, especially the 3-Valve (3V) 4.6L and 5.4L from 2004 onward, this code is the canary for timing chain stretch and the variable cam timing (VCT) phaser unlocking erratically. It rarely means a bad sensor. Cheapest-first ladder: start the engine cold and listen for the classic 3V startup rattle — a one to three second metallic chatter from the front cover means the chain tensioners have bled down overnight and the phasers are rattling on their locking pins. Scan live data and graph CMP1_DESIRED vs CMP1_ACTUAL — at idle the values should track within 1 degree; if actual hunts more than 3 degrees from desired or lags when commanded to advance under throttle tip-in, the phaser is sticking. Check oil pressure at the gauge port: 3V Modulars spec 20 psi hot idle, 45 psi at 2,500 rpm; below 15 psi hot idle the phasers cannot hydraulically lock. The expensive misdiagnosis is replacing crank and cam sensors ($80 to $200) when the actual fault is a $1,200 to $2,400 VCT phaser/chain/guide/tensioner kit.

Vehicle-specific patterns: 2004-2008 Ford F-150 5.4L 3V trucks are the textbook P1336 candidates — Ford TSB 14-0194 details the phaser/tensioner/guide kit replacement, parts run $400 to $700 OEM, labor runs $1,200 to $1,800. 2005-2010 Ford Mustang GT 4.6L 3V cars suffer the same phaser/chain wear but with easier access. 2005-2014 Ford Expedition/Navigator 5.4L 3V engines see P1336 with the cold-start rattle by 100,000 miles consistently. 2007-2014 Ford Edge 3.5L Duratec 35 (Cyclone) suffers P1336 from water-pump-driven timing chain failure — the internal water pump leaks coolant into the oil and accelerates chain wear; check oil for milkshake before condemning phasers. Estimated repair: $400 to $4,500.