So I own a 2011 Volvo XC90 which I purchased used about 5 years ago. I've had to change everything from suspension to mountings and just recently spark plugs etc. Anyway, recently it has been misfiring and the mechanic had a look at it and said I needed new ignition coils. So I preordered them and picked them up when I went to Europe (I live in Egypt). Fast forward, took the car to the mechanic with the new coils, and changed them but the car wouldn't start. What was supposed to be a 10-minute job is now a 2-week nightmare. The mechanic says the ECU is the problem and he can't find any replacement parts. He says I cannot get new ones because they will need reprogramming and apparently we don't have the software here in Egypt. So he says the best option is to get used ECU, immobilizer, and key all from the same vehicle type. I just feel drained at the moment. Any advice, or thoughts? I'll take anything at the moment.

PS I've spent quite a bit of cash fixing it already over the years

 

Are there any Volvo dealers in Egypt? (software is downloaded using a VIDA subscription) Any chance of getting the car to the Dealer service department?

If you put the old coils back in does the engine run? (still miss-firing)

Which engine do you have 5, 6, or 8 cyl?

 

It's a 6 cylinder, but only 4 work when you start it
with both old and new coils

 

Ok - start from the beginning. You have 2 cylinders miss firing. Remove coils and plugs from those 2 cylinders. What's the compression on those two? (sure if you want to be most accurate check all 6)

If compression is ok, swap those coils and plugs (if plugs are in good condition) to two other cylinders. Does the miss fire move to the new cylinders? Does your $10 noid light show a signal to all the injectors?

If so you have a bad coil or plug. Then replace only what you have proven to be bad.

But - are the two miss firing cylinders #1 and #5 (or #6 and #2) ?

Note in the wiring diagram below #1 and #5 (or #6 and #2) use a different ground wire for the coils than the other 4 cylinders.

 

So apparently there is no signal from ECU to injectors 1 and 2. If it's an ecu problem, can it be fixed? As there are no specialists here for that, would it be ok if i just travelled with the ecu say to europe to get it fixed or does the car need to be physically present? i hope i don' sound like a complete loser

 

So all coils and plugs are working. The misfire doesn't shift after swap. There is no signal from ECU to injectors in cylinder #1 and #2.

 

I know they are a long way from you but xemodex might have a repair or replace solution that will not require a software download to pair a different ECU to your car.

https://xemodex.com/us/engine-contro...les-for-volvo/

 

thanks. Found one a bit closer in Brussels. fingers crossed.

 

So I finally managed to fix the ecu. Put the new ecu in and there are no more ecu fault codes reported. However the misfire on cylinder 1 and still persists. There is absolutely no pulse on injectors 1 and 2. Any ideas on what to check for now? I replaced all the plugs and coils by the way.

 

All the injectors (8/6-8/11) get +12 volts from the green wire as shown in the wiring diagram. The injectors are grounded by the ECM. If you have +12 volts at the green wire on each injector - you could check continuity on the 6 wires injector grounding wires going to the ECM.