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Old 3rd April 2018, 18:39   #1
75driver
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Default How to remove the ECU

I want to get a 160 upgrade via post, so I had to remove the ecu.

The 1st time I done this, I was a little apprehensive, as I don’t like disturbing electrical cables. I didn’t see a “how to” at the time, so this time, I took some photos, which may be of use to anyone else having to do the same.
90% of this should be familiar, for anyone who has changed a pollen filter, or checked their plenum for water ingress, so apologies if photos look repetitive.
Edit: prior to disconnection of electrical connectors, it would be recommended to disconnect the battery. Makes sense to do this at the outset, but unfortunately not shown here.
1st I removed the rubber weather strip.

Then removed the outer grille scuttle panel by releasing the 2 tangs.

Unscrew the Philips head screw, that is secured in the plastic scrivet.

The scrivet should pop out. It looks like this.

Then remove 3 of the securing clips nearest to the near side wing.
The photo below shows I have started the furthest one.
I use a small flat blade screwdriver, with my finger held over the clip as I prise it up. They have a tendency to fly off.

The scuttle panel can be lifted up a bit, to remove the inner shield panel, by sliding it out horizontally. It may be a bit reluctant if it has never been out before, but with a bit of wiggling, it will slide out.

Now you can see the housing holding the ECU.
At the rear of the photo below, you will see a brown clip, holding the 2 main wiring looms to the ECU. This should be unclipped by prising open with a long screwdriver. Mine was already open / broken, so someone has been here before.

The ECU housing can now be lifted clear of the plenum.
Note the 2 tangs on the front, that secure the top half of the housing to the lower half.

Take note of how the main wiring looms are secured thru rubber grommets in the ECU housing.

And the way the rubber grommets interlock can be seen as the housing is opened. This will be important for re-assembley.

The top of the housing can be removed by releasing the 4 tangs...2 front and 2 rear. The ECU can now be lifted out of the housing.
(I had the ECU out a while back, and had tippexed the no. Sequence of the electrical connectors, to make sure I put it back correctly. I suspect there is only 1 way to fit them, but hey ho, good practice if you are unfamiliar with something&#128512.

Electrical connectors can be disconnected, working from 5 towards 1. Connectors 5 & 1 are just pulled straight out.

Connectors 2, 3 & 4 are disconnected by pressing in a small tang, and lowering a lever arm, to pop out the connector.

There you have it, the ECU can now be lifted out.

This would also be an excellent time to check your plenum and / or replace the pollen filter (especially on a diesel) as there is now significantly more room.

There are separate “how tos” for removal and replacement of the pollen filter, courtesy of Arctic, which I mostly used for this exercise.
Reinstallation should be a reverse of the above, but taking care to reinstall the main wiring loom rubber grommets correctly in the ECU housing.

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Last edited by 75driver; 3rd April 2018 at 22:32..
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Old 3rd April 2018, 18:45   #2
suzublu
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Very well done & nicely photographed I'm sure a moderator will be along to put it in the "How To" forum for posterity
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Old 3rd April 2018, 21:35   #3
bl52krz
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I believe that you are supposed to make sure you have disconnected the battery before removing any electrical connections.
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Old 3rd April 2018, 22:26   #4
75driver
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Quote:
Originally Posted by bl52krz View Post
I believe that you are supposed to make sure you have disconnected the battery before removing any electrical connections.


Good point. 👍
Something I forgot to do!
I’d be interested to know if the gurus who do this regularly make a point of doing this.
To err on the side of caution, Ill make sure I disconnect battery before I reconnect ECU.
I’ll edit post to recommend this.


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Old 3rd April 2018, 23:17   #5
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I never disconnect the battery, if the ignition is turned off there is no problem whatsoever........and I suspect I do this more often than most

A top tip for reassembly is to refit the grommet containing the injector loom to the ECM housing lid before you plug it back into the ECM

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Old 4th April 2018, 06:33   #6
rustymotor
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The interesting point to note is the upgrade can be done by post
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Old 14th November 2019, 14:30   #7
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Thank god these extremely helpful pics and explanations are still around. Couldn't find on a general search so switched to "images" and found the thread.

Many Thanks.
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