Bosch 0445110340 Injector: Problems, Symptoms & Replacement Guide

The Bosch 0445110340 is a common-rail diesel injector fitted across the PSA/Ford DW10 family of 2.0-litre HDi/TDCi engines. Like any high-pressure injector it wears with mileage, and when it does the symptoms are unmistakable: rough idle, a diesel knock, smoke and hard starting. This guide explains how to recognise a failing 0445110340, how to confirm it with a leak back test before spending money, and exactly what's involved in replacing it correctly.

The Bosch 0445110340 at a glance

The 0445110340 is a Bosch CRI (solenoid) common-rail injector used on the PSA DW10BTED4 and DW10CTED4 2.0-litre HDi diesel engines — the same platform shared by Citroen, Peugeot and Ford. It sprays atomised diesel directly into the cylinder at rail pressures well over 1,000 bar, timed precisely by the ECU. Because each unit is calibrated, a replacement must have its correction code written to the ECU after fitment so the engine balances fuelling across all four cylinders. You can see live availability and the exact unit for your engine on the Bosch 0445110340 product page.

Common symptoms of a failing 0445110340

A worn or sticking 0445110340 usually shows one or more of these signs:

• Hard starting, especially when hot — the classic sign of excessive internal leak-back.
• Rough or lumpy idle and a noticeable diesel knock from one cylinder.
• Black or white smoke — over-fuelling from a leaking nozzle, or unburnt fuel.
• Loss of power and poor economy as the ECU compensates for an out-of-spec injector.
• Stored fault codes such as cylinder-specific misfire or injector correction faults (e.g. P020x / P1xxx codes).
• Limp mode in more advanced cases.

These symptoms overlap with other faults, so confirm before replacing — which is where the leak back test comes in.

Why the 0445110340 fails

At DW10 rail pressures, fuel is abrasive. The usual causes are contaminated or watery fuel that scores the fine metering surfaces, a neglected fuel filter, and simple high-mileage wear of the nozzle and control valve. As internal clearances open up, more fuel escapes to the return line instead of being injected — the root cause behind most of the symptoms above. We explain the failure mechanism in depth in our how common-rail injectors work and why they fail guide.

How to diagnose it (including the leak back test)

Work methodically so you don't condemn a healthy unit:

1. Read fault codes and live data — look for cylinder-specific misfire/correction codes and check rail pressure and requested-vs-actual fuelling.
2. Run a leak back (leak-off) test — collect the return flow from each injector and compare. The cylinder returning far more fuel than the others is the prime suspect. Our step-by-step diesel injector leak back test guide walks through the method.
3. Confirm with a bench test if you want certainty — the removed injector is tested against Bosch spray and flow tolerances. See our professional injector testing service.

Only once the 0445110340 is confirmed faulty should you replace it.

Replacing the 0445110340 — step by step

1. Depressurise and clean. Relieve fuel pressure, then thoroughly clean around the injector — debris in the bore is a common cause of repeat failure.
2. Remove the injector. Disconnect the electrical connector, high-pressure pipe and return line, then withdraw the injector. Seized units may need a puller.
3. Renew the seals. Always fit a new copper washer (heat shield) and the correct seals — never reuse old ones.
4. Fit the new 0445110340 to the correct torque, reconnect the high-pressure pipe (renew if specified), return line and connector.
5. Program the injector correction code (IMA/C2I). Write the new unit's calibration code to the ECU with a diagnostic tool — skip this and you'll get rough running and codes.
6. Fix the cause. Renew the fuel filter and check for water ingress, then bleed the system and road-test.

Tip: on the DW10 it's good practice to inspect all four injectors at the same time — if one has worn out, the others are often close behind.

Vehicle applications

The Bosch 0445110340 is fitted to PSA/Ford 2.0-litre HDi/TDCi diesels built on the DW10 platform (engine codes DW10BTED4 and DW10CTED4), as used across Citroen, Peugeot and Ford models of the era — including the Citroen Berlingo. Always confirm the exact part number for your vehicle by registration or by matching the number etched on the injector body. Use our injector finder to check fitment.

Remanufactured vs new

A genuine new Bosch 0445110340 is expensive. A properly remanufactured unit is rebuilt with new wear parts, calibrated to OEM specification and bench-tested, arriving ready to fit with a test sheet and warranty — typically at a fraction of the new price. For most owners and garages it's the sensible choice. Our remanufactured injector buyer's guide explains what to check before you order.

Frequently asked questions

What are the symptoms of a faulty Bosch 0445110340?

Hard starting (especially hot), rough idle and a diesel knock from one cylinder, smoke, power loss, poor economy and cylinder-specific fault codes. In advanced cases the engine may drop into limp mode.

What engine is the Bosch 0445110340 used on?

It's fitted to PSA/Ford 2.0-litre HDi/TDCi diesels on the DW10 platform — engine codes DW10BTED4 and DW10CTED4 — used across Citroen, Peugeot and Ford models including the Citroen Berlingo. Always confirm fitment by registration or the etched part number.

Do I need to code a new 0445110340 to the ECU?

Yes. Each injector carries a calibration correction code (IMA/C2I) that must be written to the ECU after fitment so the engine balances fuelling. Skipping this step causes rough running and fault codes.

Should I replace all four injectors at once?

Not necessarily, but inspect them together. If one has worn out at high mileage the others are often close behind, so it's worth leak-back testing the full set and renewing any that are out of spec.

Is a remanufactured 0445110340 reliable?

A quality remanufactured unit is rebuilt with new wear parts, calibrated to OEM spec and bench-tested before dispatch, and comes with a warranty. Fitted correctly — with new washers, ECU coding and a fresh fuel filter — it performs to the same standard as new.