Question 1

How much is an injector for an AUDI A3 1.6 TDI 105 hp?

Accepted Answer

A remanufactured injector for the AUDI A3 1.6 TDI 105 hp starts at €216.67 per unit. This engine takes a single reference, 5WS40539: the price shown is the one part that fits your vehicle, with no variant to compare.

Question 2

Which injector reference fits the 1.6 TDI 105 hp?

Accepted Answer

The reference is 5WS40539. It is what settles the match on an AUDI A3 (8P1 / 8PA) with the 1.6 TDI 105 hp engine — not the vehicle's trade name, nor its year.

Question 3

Why is only one reference offered for the 1.6 TDI 105 hp?

Accepted Answer

Because this engine was built with a single injector type. Other A3 engines carry several references depending on the production period; here the choice is unique, which rules out any risk of error.

Question 4

Where is the reference found on an injector removed from an A3 (8P1 / 8PA)?

Accepted Answer

It is engraved on the brass body. Brass holds the engraving even on a part fouled with soot. It is the only reading that confirms the match with 5WS40539.

Question 5

What happens to the old injector from an AUDI A3 1.6 TDI 105 hp?

Accepted Answer

Part 5WS40539 is sold as an exchange unit: it has already been remanufactured and bench-tested, and the injector you remove goes back into the reconditioning circuit. Return terms are stated at checkout.

Question 6

How does exchange injector 5WS40539 differ from a new part?

Accepted Answer

An exchange injector is an original part restored to working order: wear parts are replaced, then flow and spray pattern are checked on a test bench. It carries the same reference, 5WS40539, and fits in place of the part removed.

Question 7

Does injector 5WS40539 fit every A3 (8P1 / 8PA)?

Accepted Answer

No: it matches A3 (8P1 / 8PA) models fitted with the 1.6 TDI 105 hp engine. A A3 (8P1 / 8PA) running on petrol, or at a different diesel power output, takes another reference.

Question 8

Is the year of my A3 enough to choose the injector?

Accepted Answer

No. Two A3 of the same year can take different injectors depending on their engine. It is the engine-and-power pairing — here 1.6 TDI 105 hp — that determines the reference, and the code on the removed part that confirms it.

Question 9

How do I spot a worn injector on an A3 1.6 TDI 105 hp?

Accepted Answer

On this diesel engine, a fouled or worn injector shows up as misfires under acceleration, black smoke at the exhaust, higher fuel consumption and a rough idle. These signs overlap with other fuel system faults: diagnosis is a job for a qualified technician.

Question 10

Why does my A3 1.6 TDI 105 hp go into limp mode?

Accepted Answer

On this 1.6 TDI 105 hp, the ECU limits the engine when injection pressure no longer matches what is expected for the 105 hp rated output. An injector that no longer meters correctly, or whose leak-off is excessive, is one possible cause.

Question 11

What does exhaust smoke mean on a 1.6 TDI 105 hp?

Accepted Answer

On this 1.6 TDI 105 hp diesel engine, black smoke means an over-rich burn — an injector that dribbles or sprays poorly is one candidate; persistent white smoke when cold points instead to a combustion fault. Colour guides the diagnosis, it does not replace it.

Question 12

Does a knock at idle always come from the injector?

Accepted Answer

No. The knock can come from the injector itself, but equally from the common rail, a leak-off return line or the glow plugs. Noise alone is not enough to condemn the part.

Question 13

Should all injectors be replaced together on a common rail engine?

Accepted Answer

That is the rule on this type of engine: injectors age together, and one tired part wears the others. Replacement is done as a full set as soon as one fails, using reference 5WS40539 for this 1.6 TDI 105 hp.

Question 14

How do I confirm the fault before ordering injector 5WS40539?

Accepted Answer

By a fault code read and a leak-off test, carried out by a qualified technician, before any order of reference 5WS40539. That check points to the injector at fault and separates it from a pressure fault coming from the pump — two faults with similar symptoms but different remedies.

Question 15

Does injector 5WS40539 fit straight onto a 1.6 TDI 105 hp?

Accepted Answer

Yes: reference 5WS40539 is the original fitment for an AUDI A3 (8P1 / 8PA) with the 1.6 TDI 105 hp engine, and it ships with the matching seal. Fitting and coding the injector to the ECU are a job for a qualified automotive technician.

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