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

Type: Magneti Marelli
Fits: VAG – Audi / Seat / Skoda / Volkswagen (VW)
Fuel: Petrol
Ref: ECUT211195

Note: This ECU may also fit other models.

The label on a Magneti Marelli IAW 4MV carries two codes for the same unit: the Marelli variant, such as IAW 4MV.GP, and the Volkswagen Group number, such as 036 906 034 GP. We repair all twenty-one units in this petrol family, which runs in 1.4 and 1.6 16V Volkswagen, Seat, Skoda and Audi models. Read the two codes together, check them against the engine code where you have it, and you will know which unit you are holding before it reaches our workshop.

How to read a Magneti Marelli 4MV label

The Marelli line reads IAW 4MV, then a full stop and one or two letters: IAW 4MV.AH, IAW 4MV.DD, IAW 4MV.S. The Volkswagen Group line begins 036 906 034 and closes with letters of its own. On eighteen of our twenty-one units the two sets of letters are identical, so 4MV.DD pairs with 036 906 034 DD and 4MV.HL with 036 906 034 HL.

That agreement is the first check worth making. If one line is scuffed, or a listing quotes only one number, the matching letters normally give you the other. Three units do not follow the pattern, and they have a section of their own below.

Read the letters in full as well. A single letter is a different unit from a pair that starts with it, so IAW 4MV.F is neither 4MV.FB nor 4MV.FD, and 036 906 034 S is a complete number with nothing missing after the S. The pair to watch closest is DF and FD: the same two letters in reverse order, both found in the Skoda Fabia 1.4, and two separate units recorded against two separate engine codes.

Parts listings often run the Marelli line together as IAW4MV.DD, or drop the spaces from the Volkswagen number and write 036906034DD. Those are the same references; what matters is the letters at the end, not the spacing.

The three 4MV units whose numbers break the pattern

Three units carry a Volkswagen Group number whose suffix differs from the Marelli variant. All three come from 1.6 16V engines, and each pairing is recorded consistently across independent sources, so the mismatch is genuine rather than a misprint.

• IAW 4MV.F pairs with 036 906 034 BH: Volkswagen Golf and Bora 1.6 16V, engine code AZD.
• IAW 4MV.FB pairs with 036 906 034 CP: Seat Leon 1.6 16V, also recorded in the Seat Toledo.
• IAW 4MV.GC pairs with 036 906 034 CN: Volkswagen Golf and Bora 1.6 16V, engine code AZD.

The mismatch catches people out in both directions. Someone holding a unit marked 036 906 034 BH may look for a Marelli variant ending BH and find none in our table, while someone reading IAW 4MV.FB may assume the Volkswagen number ends the same way. For these three, trust the pairings above rather than the pattern.

The F and GC units need one further step, because both sit in the Golf and Bora and both are recorded with the AZD engine code. The engine code cannot separate them, but either line of the label can: BH or 4MV.F means one unit, CN or 4MV.GC the other.

Which engine codes point to which 4MV unit

Thirteen of the twenty-one units have an engine code firmly recorded against them. For those, the code is a strong second check on the label: it seldom picks out one unit alone, but it rules most of the family out.

• BBY, six units: IAW 4MV.DD, 4MV.GP and 4MV.HL in the Volkswagen Polo 1.4; 4MV.CE and 4MV.CF in the Volkswagen Lupo 1.4; 4MV.FD in the Skoda Fabia 1.4.
• BBZ, three units: IAW 4MV.AK in the Polo 1.4, 4MV.DF in the Fabia 1.4 16V and 4MV.DG in the Seat Ibiza 1.4 16V.
• AZD, two units: IAW 4MV.F and 4MV.GC in the Golf and Bora 1.6 16V.
• BCB, one unit: IAW 4MV.DR in the Golf and Bora 1.6 16V.
• AUA, one unit: IAW 4MV.EG in the Audi A2 1.4 16V.

Read the list the other way and it works as a filter. Among the Polo units with a code on record, BBZ leads only to 4MV.AK, while BBY leaves three candidates, DD, GP and HL, for the label to decide. Two more Polo units, 4MV.DE and 4MV.S, have no code firmly recorded, so a Polo label always needs reading in full.

The Fabia is the tidiest case. Its two units split exactly by engine code, BBZ for 4MV.DF and BBY for 4MV.FD, which guards against misreading that reversed pair of letters. The Lupo is the opposite: both of its units, CE and CF, are BBY, so there the label is the only way to tell them apart.

On the 1.6 16V Golf and Bora, BCB points straight to 4MV.DR. AZD leaves 4MV.F or 4MV.GC, and that is where the BH and CN numbers from the section above settle it.

The eight 4MV units with no engine code on record

For the remaining eight units we do not state an engine code, because none is recorded consistently enough to rely on, and a wrong code here would point someone at the wrong unit. Between them, the car and the label do the work.

• Seat Ibiza 1.4: IAW 4MV.AH, 4MV.AJ and 4MV.GM. The GM unit is 16V and is also recorded in the Seat Cordoba.
• Volkswagen Polo 1.4: IAW 4MV.DE, and IAW 4MV.S, which is 16V.
• Audi A2 1.4: IAW 4MV.CA, alongside the AUA-coded 4MV.EG listed above.
• Seat Leon 1.6 16V: IAW 4MV.DS, and IAW 4MV.FB with its CP number, which is also recorded in the Seat Toledo.

The Ibiza has the widest spread. Four of our 4MV units are recorded in the Ibiza 1.4 (AH, AJ, GM and the BBZ-coded DG), and the Cordoba shares two of them, DG and GM. With that many candidates for one car, we identify an Ibiza unit from its label, never from the vehicle alone.

If your label does not begin IAW 4MV

Every unit on this page is a Magneti Marelli IAW 4MV. If the label on your engine ECU carries a different designation, it is not one of the units here, and the quickest way to look for it is by make: the Volkswagen engine ECU rundown, our Seat engine ECU write-ups, the Skoda engine ECU guide and the Audi engine ECU signpost. Every make we work on is reachable from the engine ECU repair gateway.

Sending an IAW 4MV to us for repair

We repair every unit in the table below in-house, in our own UK workshop, at component level. Each ECU is logged, inspected and electrically tested, then taken through diagnostics specific to the fault it arrived with; the repair is complete only when the unit passes final testing.

Once we know what has failed, we contact you with the findings, and no chargeable work begins until you authorise it. The unit that goes back into your car is the one that came out of it, and the repair carries a 24-month warranty.

We work as a mail-in service across the UK. Before anything travels, type both label lines into our Repair Form exactly as printed, with the model, engine size and engine code if you know it. Add what the car is doing, whether a misfire, limp mode or a non-start, and our engineers can confirm the unit against the table and plan the diagnostics before it arrives.

The table lists all twenty-one units by Marelli number, each with its Volkswagen Group number alongside and the same 24-month warranty.

Common part numbers associated with this type of unit