Hey, it looks like my 2002 Jaguar x types ECU needs to be replaced, along with the fuel injectors. My question is, if i purchased an ECU set on ebay which includes the speedometer, ecu, and key from the other car, this does not require me to program anything. If i also replace the fuel injectors, will i need to program anything? I have no experience with programming so i am hoping i can just plug it all in and it would work.

 

That sounds an unlikely plan and an unlikely situation. Avoid at all costs.

The modules almost never go wrong and anyway can be repaired.

 

My mechanic checked through the car and came to the conclusion that the ECU is not sending a signal to the second fuel injector. He claims that is the problem, I would prefer to not do anything to it but the car is in limp mode and can’t be driven. Not sure if true but he also said if I just replace the second fuel injector it would be fried right away, and if i replace the ecu and not the fuel injector it would fry the ecu. No idea if that is accurate though.

 

If the ECM is not sending a trigger signal, the injector is not damaged.
If you replace the injector, you will NOT damage an injector if the ECM is NOT sending a trigger signal.
If you have a good injector, you will NOT damage the ECM.
A harness fault or faulty (shorted) injector can overload the output semiconductor in the ECM.

 

Thats good news, since the injector could overload the output of the ECM, does that mean that the ECU is fine and the faulty injector is at fault?

 

A faulty injector that draws too much current can overload the output semiconductor.
A faulty/shorted harness can cause the same thing to the ECM.

SOMETIMES the semiconductor will just shutdown and not 'pop'.
SOMETIMES the semiconductor will be be damaged by overheating and just' pop'.

I don't know what kind of output device the ECM has.

Maybe the harness is 'OPEN CIRCUIT' and that is why no trigger to the injector?
You might 'back-probe' the ECM to see if #2 is 'happy' at the ECM housing connector with the engine running?
You might get a reading of the CONTINUITY of the circuit (including the injector) from the ECM connector disconnected from the ECM?

Lots of things to consider and some ways to diagnose.

 

Before doing this, I would swap this injector out with one of the others. Does the problem follow the injector? Does it stay with the #2 output?

If it follows, replace the injector.

If it stays, when run a jumper between the appropriate lead at the ECM and the #2 injector.

The ECM is one of the last things to replace. Usually when they go bad, there is no doubt whatsoever.