To no surprise we had another BMW 1 Series recovered in, EML come on, had cut out and now won’t start – here’s what we found, how we went about it and what the fix turned out to be.
A few car details first: 2013 BMW 1-Series, F20 shape, 118i N13 Petrol engine. Initially, this made me think of a previous job that we had in – a 3 series with this engine. It had engine oil that had made its way through the oil level sensor into the wiring harness all the way back to the DME (engine ECU), the DME was full of oil! A quick check by removing all the wiring harness plugs on the DME revealed no oil this time.
DME fault memory gave us some info to work with:
113026 Injection relay and injectors, supply voltage, fuel injection: circuit short to ground. 1F0514 Valvetronic supply voltage: circuit short to ground. 1F0515 valvetronic supply voltage: open circuit.
The faults were permanent, as soon as cleared they all come back.
A quick look at the wiring diagrams (Check out my previous post for free diagrams) showed us that the ignition coils, injectors and valvetronic system is all wired directly to the DME. A check of the wiring revealed no obvious issues. Possibly the DME could be faulty, but no one wants to jump straight to an engine DME!
A little bit of further digging in wiring diagrams found that there is a ‘Integrated Supply Module’ (Component Z11 – wiring diagram below). Essentially this is a little box with relays / fuses (that can’t be changed), that is turned on by the FEM (Front Electronic Module), and switches on power to the DME, ignition/injection and valvetronic. Based on the fault codes it would make sense that there is something wrong in this.
We checked the main power feed to this unit – all OK. next that the FEM was switching this on – all OK. Suspicion; DME faulty.
With the DME costing over £1000+ vat, we sent the unit away for testing. It was confirmed faulty and was remanufactured. A note that come back with the unit said that the defect was caused by a faulty ignition coil or faulty ignition coil wiring.
A second check of the wiring confirmed no issues here. We couldn’t risk putting the DME back on with the old coils, just in case it blew it up again, so all coils were replaced. Not mega expensive, £40 ish a piece, easy to change too.
So the assumption is that a defective ignition coil caused the DME to fail internally.
Hopefully this helps someone with the same issues!
