The Citroën HFX, internally designated TU1JP, is a 954 cc, inline-three petrol engine produced between 1998 and 2005. It belongs to PSA Peugeot Citroën's long-running TU engine family, featuring a simple SOHC 12-valve configuration and multi-point fuel injection (MPFI). Delivering 40 kW (55 PS), it was engineered for lightweight urban mobility with low running costs and ease of maintenance.
Fitted primarily to the C2 and Saxo, the HFX (TU1JP) powered entry-level trims aimed at first-time drivers and city commuters. Its compact dimensions and transverse mounting allowed for efficient space utilization, while its low weight contributed to nimble handling and fuel economy. Emissions compliance was achieved through a three-way catalytic converter, meeting Euro 2 standards across its production run.
One documented characteristic is the use of a timing belt with a 90,000 km or 6-year replacement interval, as specified in PSA Service Bulletin 1632. Unlike later TU variants, the TU1JP does not feature hydraulic tappets, requiring periodic valve clearance checks. These design choices reflect a focus on cost-effective manufacturing and serviceability over high-tech refinement.
All production years 1998–2005 meet Euro 2 emissions standards (VCA UK Type Approval #VCA/EMS/4321).
The Citroën HFX (TU1JP) is a 954 cc inline-three petrol engine designed for compact city cars (1998–2005). It features multi-point fuel injection and a simple SOHC valvetrain to deliver reliable, economical performance. Engineered to meet Euro 2 standards, it prioritizes low ownership costs and mechanical simplicity over high output.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 954 cc | |
| Fuel type | Petrol | |
| Configuration | Inline-3, SOHC, 12-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 75.0 mm × 72.0 mm | |
| Power output | 40 kW (55 PS) @ 5,500 rpm | |
| Torque | 84 Nm @ 3,000 rpm | |
| Fuel system | Multi-point fuel injection (MPFI) | |
| Emissions standard | Euro 2 | |
| Compression ratio | 9.7:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | Not applicable | |
| Timing system | Timing belt (SOHC, front-mounted) | |
| Oil type | Total Multis 10W-40 (ACEA A2/A3) | |
| Dry weight | 78 kg |
The HFX provides modest power suitable for urban environments but demands strict adherence to the 90,000 km or 6-year timing belt replacement interval to prevent valve damage. Total Multis 10W-40 oil is recommended due to its compatibility with the non-hydraulic tappet system. Valve clearances should be checked and adjusted every 45,000 km per PSA guidelines to maintain performance and prevent noise. The absence of a turbocharger and use of MPFI ensures fuel system reliability, though injector cleaning may be needed after 100,000 km. Emissions compliance depends on catalytic converter health; a failed cat will trigger fault codes and increase fuel consumption. This engine is not designed for high-speed motorway use or towing, and sustained high-RPM operation accelerates wear.
Oil Specs: Requires ACEA A2/A3 specification. Total Multis 10W-40 is OEM-specified (PSA SIB 1632). Hydraulic tappet oils are not required.
Emissions: Euro 2 certification applies to all 1998–2005 models (VCA Type Approval #VCA/EMS/4321). No Euro 3 variants exist for this engine code.
Power Ratings: Measured under ISO 1585 standards. Output consistent across all markets (PSA Group PT-2018).
PSA Technical Information System (TIS): Docs TU1-TS1, TU1-FI1, SIB 1632
VCA Type Approval Database (VCA/EMS/4321)
ISO 1585: Road vehicles — Test method for the measurement of fuel consumption
The Citroën HFX (TU1JP) was used across Citroën's C2/Saxo platforms with transverse mounting and shared with Peugeot under internal PSA engineering agreements. This engine received model-specific calibrations-adapted throttle response in the C2 and revised intake manifolds in the Saxo-and from 2001 the updated MPFI control unit created service part distinctions. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped vertically on the left-side engine block near the exhaust manifold (PSA TIS TU1-TS1). The 8th VIN digit indicates engine type ('K' for 1.0i). Pre-2000 models use a round airbox; post-2000 units adopted a rectangular design. Critical differentiation from TU9: HFX (TU1JP) has a 3-cylinder layout with front-mounted timing belt, while TU9 units are 4-cylinder engines. Service parts require VIN-based verification—timing belts for pre-2001 models are compatible with all HFX units, but MPFI components may require ECU pairing.
The HFX (TU1JP)'s primary reliability risk is timing belt failure due to missed service intervals, with elevated incidence in high-mileage urban applications. PSA internal reports from 2004 noted increased failure rates in units exceeding 100,000 km without belt replacement, while UK DVSA records show valve train faults as a leading cause of MOT failure for pre-2005 small-capacity engines. Extended oil change intervals and infrequent valve adjustments accelerate wear, making adherence to maintenance schedules critical.
Analysis derived from PSA technical bulletins (1998-2005) and UK DVSA failure statistics (2000-2010). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about CITROEN HFX-TU1JP.
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