VW / Audi / Seat / Skoda (VAG) Magneti Marelli 4LV Engine ECU Repairs

Type: Magneti Marelli
Fits: VAG – Audi / Seat / Skoda / Volkswagen (VW)
Fuel: Petrol
Ref: ECUT210195

Note: This ECU may also fit other models.

Of the nineteen Magneti Marelli IAW 4LV engine ECUs on this page, three are recorded behind a 1.6 engine and fifteen behind a 1.4. The split is uneven, and it is how this page is laid out: the short 1.6 group first, then the long 1.4 group, then the Volkswagen numbering that runs through both.

All of them are petrol units, and between them they reach Volkswagen, Seat, Skoda and Audi. The one unit placed in neither group, the IAW 4LV.UA, is listed in the table at the foot of the page.

The three 1.6 units: IAW 4LV.G, H and HA

Only three units here are recorded behind a 1.6, and they come from two makes. The G and the H are Volkswagen Golf units; the HA is a Seat unit, recorded in both the Leon and the Toledo.

The two Golf units are where engine codes earn their place. The G is recorded with the ATN engine and the H with the AUS, so a Golf 1.6 whose engine code you know points to one of the pair rather than leaving both in play.

The H carries the Volkswagen number 036 906 034 BB. The G is best confirmed from the IAW 4LV.G marking on its own case, read together with the ATN code.

The HA carries 036 906 034 BD. It is the only 1.6 unit on this page recorded in a Seat, and we give no engine code for it, so its Leon or Toledo origin and the HA label are what identify it. For a Seat engine ECU from another family, browse our Seat engine ECU archive.

Eight 1.4 units beyond the Polo

Fifteen 4LV units are recorded behind a 1.4. Seven are VW Polo units, taken together in the next section; the other eight are spread across the Skoda Fabia, the VW Lupo, the Seat Ibiza, the VW Caddy and an Audi.

The Skoda Fabia has two. The IAW 4LV.B, Volkswagen number 036 906 034 AE, is recorded with the AUA engine; the IAW 4LV.C, numbered 036 906 034 BK, with the AUB. Between these two Fabia units, the engine code is the deciding detail. Other Skoda engine ECUs are covered in our Skoda engine ECU chapter.

The VW Lupo has three: the IAW 4LV.TA (036 906 034 AQ), the IAW 4LV.UB (036 906 034 DT) and the IAW 4LV.VA (036 906 034 AT). Only the TA has an engine code on record, AUA, so for a Lupo unit the label on the case is the dependable way to tell the three apart.

The Seat Ibiza unit is the IAW 4LV.PA, numbered 6K0 906 034 F, and the VW Caddy unit is the IAW 4LV.Q, numbered 6K0 906 034 A. Both sit on the 6K0 base, which is explained further down.

The IAW 4LV.Z, numbered 036 906 034 Q, is recorded in an Audi with a 1.4 engine. The part records do not settle the model, so we name none. It is the only 4LV here recorded under Audi; for any other Audi engine ECU, see where the other Audi engine ECUs sit.

Seven 1.4 units in the VW Polo

The Polo accounts for more 4LV units than any other car on this page: the K, KA, L, N, X, XA and RA. The car and the 1.4 engine leave all seven in play, so the narrowing comes from two other details, the engine code and the base of the Volkswagen number.

Take the engine code first. AUB is recorded behind one Polo unit only, the IAW 4LV.N (036 906 034 M), and APE behind one only, the IAW 4LV.XA (036 906 034 BE), which is also recorded with AUA. AUA is shared by three: the KA, the L (036 906 034 D) and the XA.

A code points towards a unit without ruling the others out. The K, the X and the RA have no engine code we can confirm, so an AUB Polo points to the N but does not exclude those three.

The base narrows it further. The K (6K0 906 034 C) and the KA (6K0 906 034 E) carry numbers on the 6K0 906 034 base, while the other five Polo units are numbered on 036 906 034. Of the three AUA units, the KA is the only one on the 6K0 base.

The RA (036 906 034 BA) is the Polo unit that also reaches another make. It is recorded in the Seat Arosa as well, and is described as a unit for a 1.4 16V engine.

For a Volkswagen engine ECU that is not a 4LV, our register of Volkswagen engine ECUs covers the other families.

Two Volkswagen number bases: 036 906 034 and 6K0 906 034

Every Volkswagen number in the table for this family begins with one of two bases. Four units carry 6K0 906 034: the K and KA in the Polo, the PA in the Ibiza and the Q in the Caddy. The other numbers in the table begin 036 906 034.

Within this family the four 6K0 units are all 1.4s, in Volkswagens and one Seat, while 036 906 034 turns up on 1.6 units in the Golf and the Leon and on 1.4 units under all four makes. The base is a reading aid, then, not a guide to the car.

It matters most where a final letter repeats. 6K0 906 034 E belongs to the IAW 4LV.KA and 036 906 034 E to the IAW 4LV.X, and both units are recorded in the VW Polo with a 1.4 engine. Read only the last few characters and they look alike; read the whole number and they do not overlap.

The same care applies to the Marelli label. H and HA, K and KA, and X and XA are separate units with separate Volkswagen numbers, so the variant needs reading in full from the case. If the Marelli reference on your unit is not among the nineteen here, engine ECU repair at a glance shows the other families we repair.

Repairing a 4LV: what happens after it arrives

We handle the 4LV as a mail-in repair and take units from anywhere in the UK. When one arrives, the label is recorded, the case and circuit board are examined for physical damage, and the unit is tested electrically before we work towards the fault you reported.

The repair is made at component level by our own engineers in our UK workshop. The failed part is traced on the board and replaced or reworked under a microscope with temperature-controlled equipment, rather than the ECU being exchanged for another.

We tell you what we have found before anything chargeable begins, and the work goes ahead only once you have said yes. The unit is retested after the repair, returned once it passes, and the repair carries a 24-month warranty.

Before posting anything, share the full 4LV label with us through the Repair Form, adding the Volkswagen number, the car it came from and the engine code if you know it. For the seven Polo units especially, the code and the number are what help us confirm which one you hold.

The full run of nineteen IAW 4LV units follows in the table below.

Common part numbers associated with this type of unit