[Engine] Injector issues, want to check ECU connectors

[RobSt]

(Hi, first post here and I'm grateful for all the useful info I have gleaned from this forum over the years)

2013/14 Berlingo B9 1.6 HDi, low mileage 40k.

Hopefully just a simple question about ECU connectors, but a little background first:

I have had four injector-related limp mode/roadside rescues with this vehicle, three of them just this year. All four injectors have now been replaced (3 of them by myself) but one I did in February has now flagged up again. Whilst I tested zero resistance across the pins for the first two fails (so I assume definitely dead), the latest ones still have ~200kohm (which I believe it should be).
After the latest failure last week, I decided to clear the error code (Diagbox) to see what would happen; to my surprise the code hasn't returned and the engine sounds fine, although I no longer have any confidence in taking the car out for a long journey to test it properly.
Other seemingly random error codes in Diagbox disappeared when I cleared the various injector error codes, so I am wondering whether connector corrosion or an intermittent short with the harness may be causing some of these injector fail issues.

Now I think it is a common issue with this model that the scuttle below the windscreen can easily get blocked and rain water can then seep in and over the fusebox/ECU cover and consequently could cause damage within. Although things look fine at a cursory glance, I'd like to check the ECU connectors for corrosion etc. but am prevented from doing so by a steel cage fastened by shearbolts. I've seen how to remove these bolts but I would like to know if it is ok to do so and should I be aware of anything else other than disconnecting the battery before I pull the connectors?

Thanks for any advice.

[Zion]

Just switch off, with the bonnet up and wait a good 3 minutes or so before disconnecting the battery. That way you don't corrupt the BSI memory and also the ECU is disconnected with no battery on as that locks it in theft mode.

If there are still any noises coming from the car like buzzing, wait till it all stops before battery disconnection.

[RobSt]

Just switch off, with the bonnet up and wait a good 3 minutes or so before disconnecting the battery. That way you don't corrupt the BSI memory and also the ECU is disconnected with no battery on as that locks it in theft mode.

If there are still any noises coming from the car like buzzing, wait till it all stops before battery disconnection.

Thanks for that, Zion, that's reassuring to know.

[Zion]

Should clarify, for others: disconnecting the ECU plugs with the battery still connected, puts the ECU into theft mode, which is not easy to get out of and may require the help of Citroen....

Disconnecting the battery before waiting till all electronic buzzing sounds stop, can corrupt the memory in the BSI and cause issues on trying to start up.

Ideally, you want the drivers window left down and bonnet up, wait delays as above, then when reconnecting the battery then wait a few mins after putting it back on, reach in the open window, do not open the door, turn only sidelights on, key into ignition, out ignition on (red lights on dash), no start yet, hold lock button on key for 10 secs, may hear a beep from the dash, start engine.

Switch off, shut windows, check central locking works. Done.