Discovery 5 3.0 Ingenium I6 Diesel D250 to D300 Factory Upgrade

Jaguar Land Rover builds the 3.0-litre straight-six Ingenium diesel engine in a single mechanical specification and then governs output through Powertrain Control Module (PCM) calibration and Car Configuration File (CCF) settings. The D250 and D300 variants of the Discovery 5 share every physical powertrain component: the same AJ20D6 engine block, the same twin-turbocharging hardware, the same 2,500-bar common-rail fuel system, the same 48V MHEV assembly, and the same ZF 8HP automatic transmission[reference:0]. The performance difference between the two factory variants lives entirely within the software. This product page explains how the D300 factory calibration upgrade works, what it changes, and why it preserves the engineering integrity JLR designed into the Discovery 5 platform.

One Powertrain, Two Factory Calibrations

JLR calibrates the PCM to deliver different power and torque ceilings for each market position. The D250 calibration produces 249PS (183kW) at 4,000 rpm and 600Nm of torque between 1,250 and 2,250 rpm[reference:1]. The D300 calibration raises those same parameters to 300PS (221kW) at 4,000 rpm and 650Nm between 1,500 and 2,500 rpm[reference:2]. The engine, turbochargers, injectors, cooling circuit, and exhaust aftertreatment system remain identical across both variants. No mechanical component changes when you move from D250 to D300 specification.

What the D300 Calibration Delivers

The D300 factory software unlocks the full performance envelope of the Ingenium I6 diesel in the Discovery 5. Power rises by 51PS and torque rises by 50Nm, producing a measurable improvement in real-world drivability. Acceleration from 0 to 100 km/h shortens from approximately 8.1 seconds in the D250 to 6.8 seconds in the D300[reference:3]. The D300 calibration also shifts the torque plateau upward in the rev range, extending peak torque availability to 2,500 rpm and giving the engine a broader, more responsive power band for overtaking and highway merging. The 48V MHEV system synchronises with the upgraded parameters to maintain smooth torque delivery, and the Discovery 5 retains its 3,500kg braked towing capacity across both variants[reference:4].

Genuine JLR Calibration, Not an Aftermarket Remap

This upgrade uses the factory D300 calibration data that JLR validates and preloads within the vehicle’s firmware architecture. The process flashes the official PCM calibration and updates the CCF to activate the D300 powertrain flags, exactly as the production line configures a factory D300 vehicle[reference:5]. The upgrade retains full dealer diagnostic access through JLR Pathfinder and TOPIx, preserves over-the-air (SOTA) update compatibility, and maintains factory emission compliance. All safety limits, thermal protection protocols, and DPF regeneration logic remain untouched. The calibration is fully reversible: the original D250 software can be restored at any time because the process changes only software within the engine control module[reference:6].

Engineered for the AJ20D6 Architecture

The Ingenium I6 diesel—designated AJ20D6—uses a 2,997cc displacement, an 83.0mm bore, and a 92.3mm stroke, with four valves per cylinder and variable valve timing[reference:7]. The boosting system pairs two close-coupled, series-sequentially arranged turbochargers with Twin Electric Variable Nozzle Technology, delivering 90% of peak torque in just over a second at 2,000 rpm[reference:8]. The all-aluminium construction saves 80kg over the previous V8 diesel, and the engine meets RDE2 and Euro 6d-final emissions standards with 48V MHEV technology[reference:9][reference:10]. The D300 calibration operates entirely within the engineering limits JLR validated for this hardware.

Specifications

Compatibility and Process

This upgrade applies to 2021MY-onward Discovery 5 (L462) vehicles fitted with the 3.0-litre Ingenium I6 diesel in D250 specification. The procedure uses the vehicle’s ENET diagnostic port with the JLR Enet WiFi adapter for DoIP programming, and it follows the same calibration pathways JLR uses on the production line[reference:11]. You supply the VIN for compatibility verification, and the calibration flashes remotely over a secure connection. The process reads and backs up the original CCF before writing the D300 configuration, ensuring full reversibility and leaving no aftermarket modifications in the vehicle’s software architecture. The result is a genuine factory D300 specification, activated through authenticated JLR engineering access.