LLY Duramax Crankshaft Position Sensor Location

Direct answer

On the 6.6L LLY Duramax, the crankshaft position sensor is mounted at the rear of the engine block. It reads a reluctor wheel associated with the crankshaft and is typically reached from the driver side, near the transmission bellhousing area.

Scope and qualifications

The LLY designation applies to a specific 6.6L Duramax diesel configuration rather than every Duramax generation. This location should not be assumed for earlier LB7 or later LBZ and LMM engines without checking the applicable model year, because sensor routing and nearby components can differ.

How to recognize it

Look for a small electrical sensor secured by a single fastener near the rear block area. Its two-wire or three-wire connector is the main identification clue, and the sensor body is usually smaller than the camshaft position sensor. It can be easy to confuse with nearby engine-speed or transmission-related sensors, so the wiring path and mounting point are the most useful distinguishing features.

Access is often limited by the transmission and surrounding heat shields or brackets. Because mounting points and fastener styles can vary slightly by model year, the safest recognition step is to follow the sensor wiring toward the rear crank area and confirm the bracket before removal.

Evidence and uncertainty

Location and identification should be verified against service documentation for the exact model year and truck configuration. The supplied research does not include a step-by-step photo sequence or torque specification for this repair.

Practical guidance

• Identify the truck as an LLY 6.6L Duramax before using this location. • Work from the driver side near the rear of the block and bellhousing. • Follow the sensor connector rather than relying on a generic image. • Allow for limited clearance; do not force the connector or mounting bolt. • Confirm the replacement sensor connector style before ordering.