VW / Audi / Seat / Skoda (VAG) Bosch EDC15V Engine ECU Repairs

Type: Bosch
Fits: VAG – Audi / Seat / Skoda / Volkswagen (VW)
Fuel: Diesel
Ref: ECUT331350

Note: This ECU may also fit other models.

Nothing on this ECU is wired to an injector. On a VE-pump diesel the injectors are mechanical — spring and nozzle, opened by the pressure the pump puts behind them — and what this unit controls is the pump: how much fuel it delivers, and when it delivers it. These are diesel engine ECUs and we test and rebuild them in full here.

That is why the fault most people arrive with has no part in it. The car will not start, or it starts and cuts out, or it has gone flat and gutless on the road, and somebody has said the ECU. Nothing in the story names a cylinder, because on this engine there is no mechanism that could name one.

Two things on the pump answer to this ECU. One is the quantity adjuster, which sets how much fuel is delivered on each stroke. The other is the timing control valve, which sets the point at which delivery begins. The ECU reads the pedal, the engine’s speed and the sensors around it, decides both of those, and holds the pump to the answer. Starting, idling, pulling up a hill and shutting down are all the same two decisions in different proportions.

Because there is only one route from this ECU to the fuel, a fault in it does not show up as one part of the engine misbehaving. It shows up as the engine. Hard starting. Cutting out without warning. No power at all, or power that comes and goes. Running rough at idle. That is the honest shape of an EDC15V complaint, and it is the reason the fault is so hard to pin down from the driver’s seat.

It is also why the injection pump imitates this ECU so well. A pump that has worn, a quantity adjuster that has begun to stick, a timing valve that no longer moves cleanly — each of those gives hard starting, poor power and rough running as well. Two components, one job between them, and one set of symptoms shared. Injection pumps are not work we take on. The ECU that commands them is.

What separates them is the unit on its own. Tested off the car, with no pump in front of it and nothing else in the way of the result, the ECU either does what it is supposed to do or it does not, and the answer is about the unit rather than about the engine. In the car, every reading anyone takes has already passed through the pump on its way to the diagnostic socket.

Cloning, immobiliser bypass and remapping are none of them work we take on. Our part of it is the engine ECU itself, and the fault on its board.

The list below covers two engines, not one engine in versions. Much of it belongs to the turbocharged 1.9 TDI cars — the Audi A6 on the AFN engine, the Golf, and the 110 hp version among them. A large part of it does not: the naturally aspirated 1.9 SDI, which has no turbocharger at all, in the Caddy and the Seat Inca on AYQ at 64 hp and on AEY, and in the Golf and the Inca on AGP. There is a 1.7 SDI from a Lupo or an Arosa on it as well. If yours is an SDI, a great deal of what is written about the 1.9 TDI has nothing to do with your engine, and we take in both.

If what came off the car is an EDC15VM rather than an EDC15V, the Bosch EDC15VM has a page of its own.

The route through the workshop is the same for every unit. It is given its own job record on arrival, checked over physically, then put under electrical test. The result reaches you before any decision does: what the testing showed, what the repair involves, and no chargeable work until you have agreed to it. The fault is then repaired on the board your car was built around, by the engineers who tested it, in our own workshop, with no part of the job sent anywhere else. Nothing goes back until it has passed testing a second time, after the repair. The work carries a 24-month warranty.

If the car is a Volkswagen and the unit that came off it turns out to be something else entirely, start with the Volkswagen units. Everything comes in by post and leaves by post, wherever in the UK you are.

If the pump has been looked at and the engine is still doing all of it, the unit itself is what is left to prove. Add the symptoms and the numbers from the unit; the Repair Form takes both.

Common part numbers associated with this type of unit