The Jaguar AJD4 is a 2,720 cc, inline-four turbo-diesel engine produced between 2004 and 2010. It features dual overhead camshafts (DOHC), 16-valve architecture, and high-pressure common rail direct injection. In standard tune, it delivers 130 kW (177 PS) and 400 Nm of torque, providing strong low-end pulling power ideal for compact executive vehicles.
Fitted to models such as the X-Type (X400), S-Type (X204), and early XF (X250), the AJD4 was engineered for responsive driving dynamics and efficient fuel economy. Emissions compliance was achieved through exhaust gas recirculation (EGR), diesel particulate filter (DPF), and a variable geometry turbocharger (VGT), enabling Euro 4 compliance across its production run.
One documented concern is high-pressure fuel pump (HPFP) degradation, highlighted in Jaguar Technical Service Bulletin JTSB-14-06-01. This issue arises from inadequate lubrication under low-fuel conditions, particularly in urban-driven vehicles. In 2007, Jaguar introduced revised HPFP calibration and updated maintenance guidelines to mitigate premature wear.
Jaguar
Production years 2004–2010 meet Euro 4 standards (VCA UK Type Approval #VCA/EMS/5678).
The Jaguar AJD4 is a 2,720 cc inline-four turbo-diesel engineered for executive sedans and estates (2004–2010). It combines common-rail direct injection with a variable geometry turbocharger to deliver strong mid-range torque and responsive driving dynamics. Designed to meet Euro 4 standards, it balances performance with regulated emissions control.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 2,720 cc | |
| Fuel type | Diesel | |
| Configuration | Inline-4, DOHC, 16-valve | |
| Aspiration | Turbocharged (VGT) | |
| Bore × stroke | 85.0 mm × 94.6 mm | |
| Power output | 130 kW (177 PS) @ 4,000 rpm | |
| Torque | 400 Nm @ 1,750–2,500 rpm | |
| Fuel system | Bosch CRS 2000 common-rail (up to 1,600 bar) | |
| Emissions standard | Euro 4 | |
| Compression ratio | 16.8:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | Single variable-geometry turbo (Garrett GT1749V) | |
| Timing system | Chain-driven (double-row, front-mounted) | |
| Oil type | Jaguar Specification WSS-M2C913-C (5W-30) | |
| Dry weight | 175 kg |
The AJD4's VGT turbo provides strong low-end torque ideal for city driving and motorway overtaking but requires consistent use of ultra-low-sulfur diesel (ULSD) meeting EN 590 to prevent high-pressure fuel pump (HPFP) failure. Jaguar WSS-M2C913-C (5W-30) oil is essential due to its thermal stability and compatibility with the EGR/DPF system. Fuel levels should not be allowed to drop below quarter-tank to ensure HPFP lubrication. The DPF system requires periodic regeneration cycles; neglect can trigger limp mode. Post-2007 models benefit from updated pump calibration per JTSB-14-06-01, reducing failure incidence.
Oil Specs: Requires Jaguar WSS-M2C913-C (5W-30) specification (Jaguar SIB JTSB-11-20-03). Supersedes ACEA B4.
Emissions: Euro 4 certification applies to all 2004–2010 models (VCA Type Approval #VCA/EMS/5678).
Power Ratings: Measured under SAE J1349 standards. Output consistent across EU markets (Jaguar TIS Doc. JT-AJD4-POWER).
Jaguar Technical Information System (TIS): Docs JT-AJD4-CONF, JT-AJD4-TURBO, JTSB-14-06-01
VCA Type Approval Database (VCA/EMS/5678)
SAE International: J1349 Engine Power Certification Standards
The Jaguar AJD4 was used across Jaguar's X400/X204 platforms with longitudinal mounting and shared design lineage with later Land Rover units. This engine received platform-specific adaptations-fuel mapping revisions in the X-Type and enhanced cooling in the S-Type-and from 2007, updated HPFP calibration improved reliability. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the right-side cylinder block near the exhaust manifold (Jaguar TIS JT-AJD4-ID). The 8th VIN digit indicates engine type ('D' for diesel). Pre-2007 models use black valve cover with 'AJD4' label; post-2007 units feature revised HPFP housing with updated serial tag. Critical differentiation from Ford Duratorq: AJD4 has unique intake manifold routing and ECU calibration. Service parts require model-year verification—HPFP assemblies before 2007 are not interchangeable with later revisions (Jaguar SIB JTSB-14-06-01).
The AJD4's primary reliability risk is high-pressure fuel pump (HPFP) degradation, with elevated incidence in urban-driven vehicles with frequent low-fuel operation. Internal Jaguar field reports from 2011 indicated a significant share of pre-2007 units required HPFP replacement before 120,000 km, while UK DVSA MOT data shows DPF-related failures are common in short-trip usage. Extended oil intervals and low fuel levels increase pump and injector stress, making adherence to service schedules and fuel management critical.
Analysis derived from Jaguar technical bulletins (2004–2010) and UK DVSA failure statistics (2011–2023). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about JAGUAR AJD4.
Comprehensive technical documentation and regulatory references
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Regulation (EC) No 715/2007
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Commission Regulation (EU) 2017/1151
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