Ford Ka 1.3 Not Firing on Cylinders 1 and 4: Visteon EEC-V Engine ECU 1S5F-12A650-AB Repaired

Cylinders 1 and 4 were not firing on this Ford Ka 1.3, whose engine was running rough. The car was diagnosed as having a faulty engine ECU, a Visteon EEC-V with the Ford number 1S5F-12A650-AB, and the customer sent the unit in for testing and repair.

It failed on our testing rig, which confirmed that the misfire was being caused by the ECU. We replaced a damaged component and repaired corrupted injector drivers; the unit then passed final testing and went back to the customer fully working.

Cylinders 1 and 4, named from the start

The record for this job does not describe a misfire in general terms. It names the cylinders: 1 and 4. This page keeps to that wording, because it is what the customer found on the car, and it is the complaint everything we did afterwards had to answer.

The record does not say who made the diagnosis of a faulty engine ECU, or how it was reached. It says the car was diagnosed that way, and that the unit came to us next.

Where our testing rig came in

A diagnosis made on the car points at the engine ECU. Once the unit has been sent in, it is on its own, off the car, and our testing rig is where that diagnosis is either borne out or not.

This unit failed on the rig, and that failure confirmed the misfire was being caused by the ECU. From then on, the fault on cylinders 1 and 4 had its source inside the unit.

Rig testing sits inside a set sequence. Every unit posted to us, from anywhere in the UK, is logged, inspected and tested electrically, then taken through diagnostics matched to the reported fault. You can read each stage a unit goes through here before sending anything.

No repair work starts until the customer has had our findings and agreed to go ahead.

A combination of software and hardware faults

That is how the job record sums up what we found: corrupted injector drivers and a damaged component. The record does not break the phrase down any further, and this page does not either. It does not name the component, or describe what the corruption looked like.

What it does record is the repair. We replaced the damaged component and repaired the corrupted injector drivers. Changing a component on an engine ECU board is done under a microscope, and the rework equipment we use for it is temperature-controlled.

Passed on the final testing rig, returned fully working

Testing had placed the misfire inside the ECU. After the repair, the unit went onto our final testing rig and passed; a repair is not complete here until it does.

It went back to the customer fully working, with our 24-month warranty on the repair. The record covers the unit, not the car, so this page makes no claim about how the Ka ran once the unit was refitted.

Sending a 1S5F-12A650-AB engine ECU to us

1S5F-12A650-AB is on record from the Ford Ka in several sources, and the car in this job was a Ka 1.3. The Ford number ends in the two letters AB; a unit whose final two letters differ carries a different number, and should go on the Repair Form under its own.

If your Ka’s unit carries another number, look for it among the Visteon and other Ford families we list. If the car has another maker’s name on the bonnet, we list the other makes we repair separately.

If your Ka has the same unit and a misfire you have traced to particular cylinders, use the Repair Form to tell us which cylinders are not firing, along with the full Ford number from its label.