AJ133 Jag to RR Swap
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Thread: AJ133 Jag to RR Swap

  1. #1
    Join Date
    June 7th, 2019

    AJ133 Jag to RR Swap

    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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  3. #2
    Join Date
    October 2nd, 2013
    Grapevine TX

    Re: AJ133 Jag to RR Swap

    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.


  4. #3
    Join Date
    January 29th, 2007
    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.
    2008 Alaska white SC with 128,000 mi. latest diff folly. 2004 Epson green 275k kms now for sale. also 1952 Hough payloader 1959 Nuffield 4DM
    2000 kent green 4.0 SE sold
    2003 GMC 1500 AWD window van 5.3 L love it in the snow & rain-anytime [on mich ltd m&s ll] 200 plus K miles. getting very rusty.

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