Thread: Changing the ECU on a Discovery 2 V8. - You must have a Nanocom or similar.

I have just replaced my ECU with a spare. I am thinking of send it over to get it "chipped".

1). Obtain spare ECU with matching part numbers.
2). Disconnect negative battery lead.
3). Undo front panel under dash (10c coin or strong fingernail)
4). Remove front panel (4 x 8mm bolts). - Good time to clean it as if it was like mine, covered with grime and fluff.
5). Remove OBD II plug from black panel.
6). Carefully remove two black plastic "christmas tree" plugs and remove black panel under dash.
7). Remove kick panel (2 x plastic christmas tree plugs).
8). Carefully un-clip and remove 6 plugs from ECU. First and last are squeeze plugs, the others are lever lock.
9). Undo 2 x 10mm plastic nuts holding the ECU in place. Wriggle and then remove the ECU.
10). Double check existing ECU with replacement.
11). Re-attach the new ECU. I only finger tighten until car started.
12). Re-attach cables - they only go in one way and one slot.
13). Re-attach the negative terminal at the battery.
14). Plug In your Nanocom and turn the ignition on.
15). Access Discovery 2 -> Motronics -> Motronics -> Faults and clear any.
16). Go up a level, then page down and access Utility.
17). Select Discovery Security Learn. (This function forces the Motronic ECU to learn the incoming code from the existing BCU in a Discovery Series II as its correct mobilization code.)
18). Turn off the car, then disconnect/reconnect the negative terminal and start the car. All should work!
19). Tighten up tha plastic nuts holding the ECU and replace the trim.
20). Reset the Adaptive Values (second option on Utility page.) (The adaptive values should be reset if any of the following components have been renewed or rectified: fuel injector, lambda sensor, fuel pump, fuel rail, MAFS, inlet manifold, after fixing an air leak or if a new ECU was fitted.)
21). Go for a test drive.

It took me several attempts to get the immobilizer to clear. It is important that no error messages are logged by the ECU. Apart from working upside down to see clearly under the dash, no special tools or procedures were required to complete this task. It took me longer as I also clean some of the crap in and around the area and tidied wiring that I had added but did have clear access under the dash.

Originally Posted by Pedro_The_Swift

When I changed the engine ECM I'm fairly certain I just un/replugged it in........
Everything stayed the same,, except the midrange , my bum dyno told me stuff had changed

Thanks for the list...

I replaced mine and had to do the security learn as it would not start. All readings on the vehicle stayed the same ie Distance on odo.