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Hello Folks! I am brand new to this board, although I have been doing a lot of trolling over it the last couple of weeks. Lots of good info.

I also have a similar post on a Jaguar motor forum.

I have a 2012 RR 5.0 with an AJ 133 engine that overheated so badly that the motor needed replacement. I replaced the motor with a Jaguar AJ133, which was the same motor that was in the Rover . I swapped over the oil pan, pickup and exhaust manifolds. I used the original wiring harness from the range rover and am using the original range rover ECU and key.

I do not know why this is happening, but it will intermittently crank over and has a "cannot communicate with ecu" code.

I have tried using the other ECU from the Jaguar motor and that comes up with an "incorrect vin" code.

Do you think flashing the ECU would fix this?

Thank you in advance to anyone and everyone - suggestions or help greatly appreciated.
 

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The hardware (motor) shouldn't make any difference.

As you noted, it was necessary to replace the engine harness as the connector plugs to the ECM are different, which means you should be using the original ECM.

FWIW, ECU's can't be "re-flashed" (but SDD can load the security aspect of the original VIN's software and get the vehicle running for a while) between vehicles long-term so buying a used ECM on a MY2010-2012 is a temporary measure at best.

Thus, it will operate for a short while but eventually the immobilizer will throw a code and the CEL will illuminate due to incompatible VIN's.

If you have access to SDD, run the immobilizer program again making sure that SDD identifies/reads the original VIN, then run the program with it's original ECM and key.

That should ensure that the car should start and run as delivered, regardless of the engine hardware you've replaced.

Make sure that the two large ECM connector plugs are fully seated. If unsure, withdraw them both and check that the ECM's pins are all still vertical and one or two haven't been bent.

There is also a shop test called a pin-drag test that you might want to consider.

Although time consuming, the idea is to ensure that the female pins in the two connectors are not too "loose" for them to wiggle on the ECM's pins and create intermittent faults.

You remove the two multi-pin connector sockets and, with an appropriate sized male pin, insert that pin into the female pin(s) and see how "tight or loose" the female connector is.

Rob
 

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Rob. Thx for the advice on checking the connectors as my incorrect trans overheat message and subsequent distress to the trans and motor may be a result of a loose pin losing the connection momentarily. Getting a used trans controller to see if any possible chance the trans computer is toast. I have checked the trans temp sensor numerous times and always comes up to the spec resistance that rrphil has provided. Next step will be the harness of this does not solve.
 
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