Misfiring, cut-outs, fault code on cylinder 3 — the injector gets blamed, but the problem sits in the ECU. A common EDC17 defect and how to recognise it.
A classic scenario in the workshop: the customer arrives with misfiring, cylinder cut-outs and a fault code like 'Injector circuit cylinder 3'. The injector is replaced — the fault remains. The actual cause: a burned-out injector driver IC in the EDC17 control unit.
The injector drivers in EDC17 control units directly control injection pressure. They are among the most heavily loaded components. At high mileage, voltage spikes or short circuits at the injector, the driver IC can burn out. The result: the affected cylinder is no longer activated.
How to recognise that the control unit is the cause: injector and wiring checked — everything fine, fault remains; fault code disappears after clearing but returns after a short drive; multiple cylinders affected but not simultaneously (drivers burning out one after another); control unit shows elevated quiescent current on closer diagnosis.
In this case, only a repair of the control unit helps: the defective driver IC is identified and replaced at board level. The unit stays original — no recoding, no immobiliser adaptation. Via the mail-in service the unit can be sent in directly, with vehicle data and fault code log.