Description
Fuel Temperature Sensor for Citroën and Peugeot vehicles with 2.0 HDi RHY engines with Siemens injection.
Product Overview
This fuel temperature sensor is a direct-fit replacement commonly referenced under part number 1579AY. Designed for PSA/Stellantis HDi diesel systems with Siemens injection components, it provides accurate fuel temperature data to the engine management system to help maintain correct injection timing and rail pressure. Frequently searched by part number 1579AY, this item is aimed at professional technicians and DIY mechanics who service Citroën and Peugeot diesel vehicles.
Technical Information
- Manufacturer: Stellantis (Citroën / Peugeot)
- Model: 2.0 HDi RHY Engines
- Product Codes: 1579AY
- Additional Numbers: NFP
Function And Benefits
The fuel temperature sensor measures the temperature of the diesel in the supply system and sends that information to the engine control unit. The ECU uses this data to adjust injection timing, fuel quantity and compensation maps for cold start and emission control. Replacing a faulty sensor restores precise fuel metering, improves cold-start behaviour, reduces smoke and helps maintain fuel economy.
Fitment And Compatible Models
Compatible with Citroën and Peugeot vehicles equipped with 2.0 HDi RHY engines featuring Siemens injection. Typical applications include but are not limited to:
- Citroën Berlingo (models with 2.0 HDi RHY)
- Citroën Xsara (models with 2.0 HDi RHY)
- Peugeot 307 (models with 2.0 HDi RHY)
- Peugeot Partner (models with 2.0 HDi RHY)
Replacement Guide
Basic replacement steps (professional workshop procedure recommended):
- Relieve fuel system pressure and remove any residual fuel in the work area to avoid spills.
- Disconnect the negative battery terminal for safety.
- Locate the fuel temperature sensor (typically on or near the fuel rail/fuel system plumbing on HDi engines).
- Carefully disconnect the electrical connector, inspect for corrosion or damage and note connector orientation.
- Unscrew or unclip the sensor from its mounting point, taking care to catch any escaping fuel in a suitable container.
- Fit the new sensor with a new sealing washer or O-ring if supplied; tighten to manufacturer recommendations (avoid over-tightening).
- Reconnect the electrical connector, reconnect the battery, and prime the fuel system according to manufacturer procedure.
- Start the engine and check for leaks and correct operation. Clear any related fault codes with a diagnostic tool if necessary.
Installation Recommendations
- Use a new sealing washer or O-ring when installing the new sensor to ensure a leak-free seal.
- Inspect and clean the connector and wiring; apply dielectric grease to the connector pins to prevent corrosion.
- Do not force connectors; ensure clips and locks are fully engaged.
- Check for fuel leaks after installation and verify proper operation with a diagnostic tool if available.
Why The Part Fails
Common causes of failure include contamination from dirty fuel, degradation of the sensor element due to prolonged thermal cycling, moisture or corrosion of the electrical connector, and mechanical damage during previous service. Faulty readings typically result in poor cold-start behaviour, increased smoke or illumination of engine warning lights.
Recommended For
Professional technicians and experienced DIYers working on Citroën and Peugeot HDi diesel engines who need a reliable replacement for an OEM-style fuel temperature sensor. Ideal when diagnosing fuel temperature related faults or when restoring correct fuel metering after fuel system repairs.
Notes
Frequently referenced by part number 1579AY. Always follow vehicle manufacturer safety and service procedures during replacement.
