Volvo T5 S60 2012 misfire

The issue occurred on the highway. No previous issues concurrent to errors below have ever occurred.
Cylinder 2 and 4 report misfire. Replaced all 5 ignition coils. Replaced all 5 spark plugs (Iridium Bosch).
Replaced fuel Injector for Cylinder 2 and 4. I can remove injector cap on cylinder 1,3,5 and motor will shake vigorously.
Remove the injector cap from cylinder 2 or 4 or both at the same time and engine misfire remains consistent (same vibration - exhaust tone)

Took the car to Import repair center. Best advice given: “replace motor”

My question is two-fold: How do I diagnose a possible electrical issue between the computer and wires leading to the fuel injectors?
Would reflashing the ecu help?

For an engine that still runs, with semi-low milage and consistent service pattern, does the advice given from the repair center seem logical?

Thanks for any assistance you can provide. Any thoughts or suggestions are more than welcome.


The shop may have done a compression test or cylinder leak down test and determined that the engine had catastrophic damage. Ask them why they recommended engine replacement. Or have someone do a cylinder leak down test.

Good advice above. A cylinder misfire will occur if the cylinder compression isn’t working, either b/c of worn rings, or valve problems. If a compression and leak down test on those cylinders passes however, it likely isn’t going to need an engine replacement.

So what then? hmmmm… the problem would almost certainly be either fuel or spark. I guess I’d bring out my lab o-scope and take a look at the electrical signals for the sparks on those two cylinders, and the signals which fire the injectors. And compare the good cylinders to the bad ones. That should provide a clue. Your shop may be able to do this with the Volvo scan tool more easily than with an o’scope. Could be an injector- transistor driver has gone kaput on the ECU for example. Re-flashing the ECU won’t help that.