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

Type: Magneti Marelli
Fits: VAG – Audi / Seat / Skoda / Volkswagen (VW)
Fuel: Petrol
Ref: ECUT209195

Note: This ECU may also fit other models.

Start with the car: a Seat Leon 1.4, a VW Golf 1.4 or a VW Polo 1.4 16V. Two of those lead to a single Magneti Marelli IAW 4CV; the Polo leads to two, and the label on the case settles which.

Every 4CV on this page is a petrol engine ECU. The cars on record for them are Volkswagens and one Seat, so the same Marelli family turns up under two marques.

Which 4CV your car leads to

Begin with the car the unit came out of. In the records we rely on, each 4CV described here sits in one model, and each model leaves this many candidates:

• Seat Leon 1.4: one unit, the IAW 4CV.S1
• VW Golf 1.4: one unit, the IAW 4CV.V0
• VW Polo 1.4 16V: two units, the IAW 4CV.V2 and the IAW 4CV.V3

The Marelli reference on the label is read in two parts: IAW 4CV is the family, and the letter and digit after the dot are the variant. That variant is what each route above ends at.

Two of the three routes finish at a single unit. The Polo route does not, and it has its own section below.

Seat Leon 1.4 and VW Golf 1.4: one unit each

A 4CV from a Seat Leon 1.4 points to the IAW 4CV.S1. Its Volkswagen part number is 036 906 014 AQ, a pairing that recurs across the records, so expect to see both on the case.

The Leon is the only Seat these units are recorded in. For a unit from another Seat, look through the Seat engine control modules we see.

A 4CV from a VW Golf 1.4 points to the IAW 4CV.V0. Among the units on this page, the Golf leads to the V0 and to nothing else.

Neither car leaves a choice to make. The variant code on the label should simply match the one given here, and if it does not, tell us what it says before the unit goes anywhere.

VW Polo 1.4 16V: the route that splits

The Polo is where the route divides. Two 4CV units are recorded in the VW Polo, the IAW 4CV.V2 and the IAW 4CV.V3, and the engine for both is the 1.4 16V.

Knowing the model and the engine therefore still leaves two candidates, and the next step has to come from the unit itself.

Look first at the variant after the dot, V2 or V3; it names the unit outright.

The Volkswagen number is a second check for the V3. Its number is 036 906 014 BN, so a label showing that number belongs to a V3.

The V2 is also recorded with the AHW engine code. Note it if your paperwork shows it, but this page does not use the engine code to separate the two Polo units; the variant does that.

If the label is worn and the variant cannot be read, pass on whatever you can make out; our engineers will establish which unit it is rather than guess.

Holding a loose 4CV with no car to go on

A garage or trade buyer may have the unit in hand and no car to check it against. The route then runs the other way, from the label to the car:

• IAW 4CV.S1 or 036 906 014 AQ: Seat Leon 1.4
• IAW 4CV.V0: VW Golf 1.4
• IAW 4CV.V2: VW Polo 1.4 16V
• IAW 4CV.V3 or 036 906 014 BN: VW Polo 1.4 16V

For a unit from a Volkswagen other than the Golf or Polo, turn to further Volkswagen engine controllers.

A reference that appears neither in this list nor in the table below belongs to a different engine ECU, and our engine ECU repair menu is the place to find it.

What happens once your 4CV reaches us

Customers anywhere in the UK post their 4CV to us. On arrival it is recorded, examined visually and tested electrically, and diagnosis then follows the fault you described.

The repair is carried out entirely in-house and at component level. The failed part on the board is dealt with under a microscope, using temperature-controlled rework equipment, instead of the complete ECU being replaced.

We report the findings first, and the repair waits for your decision. A repaired 4CV is tested again before it goes back, and the work carries a 24-month warranty.

Write down the Marelli reference, any Volkswagen number on the label and the car the unit came from, then have your 4CV identified before it travels through the Repair Form.

The table below holds every IAW 4CV reference we repair.

Common part numbers associated with this type of unit