The Citroën 4HU, also known as P22DTE, is a 2,230 cc, inline-four turbo-diesel engine produced between 2004 and 2011. It features common rail direct injection, a variable geometry turbocharger (VGT), and DOHC 16-valve configuration. In standard form, it delivers 120 kW (163 PS) and 340 Nm of torque, offering strong mid-range performance and improved efficiency over earlier diesel units.
Fitted to models such as the Citroën C5, C6, and Peugeot 607, the 4HU (P22DTE) was engineered for executive comfort and long-distance cruising. Emissions compliance was achieved through exhaust gas recirculation (EGR), diesel particulate filter (DPF), and advanced common rail injection, enabling Euro 4 compliance across its production run.
One documented concern is high-pressure fuel pump (HPFP) failure, particularly on units with high mileage or poor fuel quality exposure. This issue, referenced in PSA Technical Service Bulletin TSB00162, is attributed to wear in the internal cam lobes of the Bosch CP3 pump. From 2007, PSA introduced revised pump calibration and updated fuel filtration standards to improve durability.
All production years 2004–2011 meet Euro 4 emissions standards (VCA UK Type Approval #VCA/EMS/6789).
The Citroën 4HU (P22DTE) is a 2,230 cc inline-four turbo-diesel engine designed for executive applications (2004–2011). It combines common rail direct injection with a variable geometry turbocharger to deliver responsive power and refined driving characteristics. Designed to meet Euro 4 standards, it balances performance with emissions control in premium PSA vehicles.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 2,230 cc | |
| Fuel type | Diesel | |
| Configuration | Inline-4, DOHC, 16-valve | |
| Aspiration | Turbocharged | |
| Bore × stroke | 85.0 mm × 99.0 mm | |
| Power output | 120 kW (163 PS) @ 4,000 rpm | |
| Torque | 340 Nm @ 2,000 rpm | |
| Fuel system | Bosch CRS 2-20 common rail (up to 1,600 bar) | |
| Emissions standard | Euro 4 | |
| Compression ratio | 17.5:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | Single variable geometry turbo (Honeywell GT1749V) | |
| Timing system | Double row roller chain (rear-mounted) | |
| Oil type | SAE 5W-40 (PSA B71 2290) | |
| Dry weight | 182 kg |
The VGT turbo provides strong low-end torque ideal for relaxed cruising but demands consistent use of high-quality diesel (EN 590 ULSD) to prevent HPFP and injector damage. Use of SAE 5W-40 oil meeting PSA B71 2290 is essential to protect the rear-mounted timing chain system. Extended oil intervals beyond 15,000 km increase risk of chain wear, especially in stop-start driving. The Bosch CP3 fuel pump is sensitive to water and particulate contamination; service the fuel filter every 30,000 km. Post-2007 engines benefit from revised pump calibration; pre-2007 units should be monitored for fuel pressure fluctuations per PSA TSB00162. DPF regeneration cycles require regular highway runs to prevent clogging.
Oil Specs: Requires SAE 5W-40 meeting PSA B71 2290 (PSA SIB TSB00162). Not compatible with low-SAPS C3 oils.
Emissions: Euro 4 certification applies to all 2004–2011 models (VCA Type Approval #VCA/EMS/6789).
Power Ratings: Measured under ISO 1585. Output consistent across fuel grades RON 51–52 (PSA TIS Doc. C22200).
PSA Technical Information System (TIS): Docs C22200, C22501, C22802, TSB00162
VCA Type Approval Database (VCA/EMS/6789)
ISO 1585: Road vehicles — Methods of measurement of fuel consumption and range
The Citroën 4HU (P22DTE) was used across Citroën's C5/C6 platforms with longitudinal mounting and shared within the PSA Group for use in Peugeot executive models. This engine received platform-specific adaptations-tuned intake manifolds in the C6 and revised exhaust routing in the 607-and from 2007 the facelifted C5 Phase 3 adopted updated ECU calibration for improved DPF regeneration, creating interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the rear left side of the cylinder block near the transmission bellhousing (PSA TIS C22200). The 8th VIN digit indicates engine type ('K' for 2.2L HDi). Pre-2007 units have silver valve covers with black plastic timing covers; post-2007 models use black valve covers. Critical differentiation from non-turbo variants: 4HU (P22DTE) includes turbocharger, intercooler, and DPF system. Service parts require model-year verification—fuel pumps for pre-2007 engines are not compatible with post-update units due to revised internal calibration and ECU mapping (PSA TSB00162).
The 4HU (P22DTE)'s primary reliability risk is high-pressure fuel pump failure in early production units, with elevated incidence in high-mileage vehicles used for short urban trips. PSA internal reports from 2006 indicated a measurable number of pre-2007 engines requiring HPFP replacement before 160,000 km, while VCA MOT data shows DPF clogging as a secondary cause of emissions-related failures. Extended oil intervals and use of non-compliant 5W-40 oil increase chain and bearing wear, making adherence to 15,000 km service intervals critical.
Analysis derived from PSA technical bulletins (2004-2011) and UK DVSA failure statistics (2005-2015). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about CITROEN 4HU-P22DTE.
Comprehensive technical documentation and regulatory references
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