BulletBrindle
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- Worcestershire
May 22 update - my ECU stopped working, so there must be something wrong with it beyond the big caps
***Just because this worked for me, doesn't mean it will for you. This could wreck your ECU permanently***
Thanks to eprothe for the inspiration - https://www.landyzone.co.uk/land-rover/ecu-problems.366226/page-2
If you're going to give it a try, please read the whole thing before jumping in and check out the photos...
I thought I put a quick post together to describe how I fixed my own ECU, in case anyone else wanted to give it a try on their own one. As these ECUs are getting quite old now, it may be a good preventative measure to do on working ones too.
A quick bit of background - my ECU failed last year with two errors codes - Topside switch failure and injectors 1-5 open circuit. Basically, the engine would crank, but no fuel was being injected. Fortunately, I sorted a spare ECU without any trouble, which kept me going for the past few months, and the broken ECU just sat in the cupboard.
I decided that I really should try and sort out a spare ECU, as I really don't want to get stranded again, especially down some green lane in the back end of nowhere.
I leant that it is usually the two big caps that fail, so I thought replacing those was a good place to start. After much searching, I managed to find some suitable capacitors with proper screw terminals and mounting studs, one of which is a perfect drop-in replacement, and another which will fit with a little effort/modification (nothing too drastic, I promise).
The 100V cap is a Kemet PEH169PA4100QB2 and the 40V is a Kemet PEH169KA4330QB2. Places like Mouser or Digikey resell these. Watch out for lead-times...
The first step is to get the cover off and inspect the PCB. There are 4x torx security bots to remove, which is the easy bit, and you then have to pry off the top cover, as it is held in place by some kind of sealant. I don't have a good way to do this - I think I just worked my way around with a large flat blade screwdriver. Undoubtably there's a better way, but I don't know what it is.
Once inside, you need to thoroughly inspect the PCB and the smaller components. If there are any signs of charring of the PCB or damage to any of the smaller components, then I doubt this will work for you. Fortunately, my PCB looked brand new.
If yours looks good too, then the next challenge is to remove the two big capacitors. Firstly you will want to make sure both caps are fully discharged - I'll let you decide how to do this, as I won't recommend what I did.
Once your caps are discharged, then remove the large nut the holds it in place and then start to undo the 4 small bolts at the front of the caps. You won't be able to undo them all yet...
The next step involves the first permanent modification of the ECU - you need to cut out a piece of metal that the big mounting stud on the cap currently passes through. I found that with some snips I was able to cut out enough metal to free the cap from the mount, but still leave enough metal there so that I could mount the new cap in the same way.
Once done, you should then be able to lift the caps up, which will give you enough movement to finish undoing the small bolts at the front of the caps. Once the caps are fully removed, unless the small bolts and locking washers look pristine, I would discard them and buy new ones (mine were corroded and/or dirty). Replacements can be bought from screwfix for less than a fiver (I used M5 x 8mm bolts, but I think the originals were M5x 10mm).
I would recommend giving the 4 contacts that the bolts pass through a good clean before reassembly.
The new 100V cap can now be installed. Makes sure that the positive terminal is located in the right place, and then fix it in place (don't forget the lock washers). Getting the new mounting bolts to bite into the threads on the cap can be a bit fiddly, and you may well find that you have to bend the metal mounting 'frame' that surrounds the caps. I found that holding the whole ECU upright so that the bolts were screwing downwards into the caps was the best way. Once you've got them both to bite, then it should be just a matter of doing them up and then sliding the mounting stud into the slot that you cut.
Installation of the 40V is a little more challenging, as you may have noticed that it is a little longer than the old one that you removed. This is where the next permanent modification comes in - you need to snip off a plastic '+' shaped stud that projects from the front of the mounting frame below the two contacts. Then, with some needle nosed pliers, I bent both the front and rear sections of the mounting frame to make the opening for the cap a bit longer - take it easy with this bit, as you don't want to break any of the legs away from the PCB. Do it little by little, offering up the cap to check if you've got enough space yet.
Once it looks like you've got enough space, now is the time to try and get the small bolts to bite into the contacts on the cap (lock washers!) Once done, then it is a case of tightening them bit by bit, and sliding the mounting stud down into the rear support (you may need to bend the support backwards with the pliers while doing this). Once in, then fully tighten all bolts and nuts on the studs (don't over do it here).
Makes sure there is no debris inside, and then pop the lid on temporarily.
That should be it. Time to give it a try!
***Just because this worked for me, doesn't mean it will for you. This could wreck your ECU permanently***
Thanks to eprothe for the inspiration - https://www.landyzone.co.uk/land-rover/ecu-problems.366226/page-2
If you're going to give it a try, please read the whole thing before jumping in and check out the photos...
I thought I put a quick post together to describe how I fixed my own ECU, in case anyone else wanted to give it a try on their own one. As these ECUs are getting quite old now, it may be a good preventative measure to do on working ones too.
A quick bit of background - my ECU failed last year with two errors codes - Topside switch failure and injectors 1-5 open circuit. Basically, the engine would crank, but no fuel was being injected. Fortunately, I sorted a spare ECU without any trouble, which kept me going for the past few months, and the broken ECU just sat in the cupboard.
I decided that I really should try and sort out a spare ECU, as I really don't want to get stranded again, especially down some green lane in the back end of nowhere.
I leant that it is usually the two big caps that fail, so I thought replacing those was a good place to start. After much searching, I managed to find some suitable capacitors with proper screw terminals and mounting studs, one of which is a perfect drop-in replacement, and another which will fit with a little effort/modification (nothing too drastic, I promise).
The 100V cap is a Kemet PEH169PA4100QB2 and the 40V is a Kemet PEH169KA4330QB2. Places like Mouser or Digikey resell these. Watch out for lead-times...
The first step is to get the cover off and inspect the PCB. There are 4x torx security bots to remove, which is the easy bit, and you then have to pry off the top cover, as it is held in place by some kind of sealant. I don't have a good way to do this - I think I just worked my way around with a large flat blade screwdriver. Undoubtably there's a better way, but I don't know what it is.
Once inside, you need to thoroughly inspect the PCB and the smaller components. If there are any signs of charring of the PCB or damage to any of the smaller components, then I doubt this will work for you. Fortunately, my PCB looked brand new.
If yours looks good too, then the next challenge is to remove the two big capacitors. Firstly you will want to make sure both caps are fully discharged - I'll let you decide how to do this, as I won't recommend what I did.
Once your caps are discharged, then remove the large nut the holds it in place and then start to undo the 4 small bolts at the front of the caps. You won't be able to undo them all yet...
The next step involves the first permanent modification of the ECU - you need to cut out a piece of metal that the big mounting stud on the cap currently passes through. I found that with some snips I was able to cut out enough metal to free the cap from the mount, but still leave enough metal there so that I could mount the new cap in the same way.
Once done, you should then be able to lift the caps up, which will give you enough movement to finish undoing the small bolts at the front of the caps. Once the caps are fully removed, unless the small bolts and locking washers look pristine, I would discard them and buy new ones (mine were corroded and/or dirty). Replacements can be bought from screwfix for less than a fiver (I used M5 x 8mm bolts, but I think the originals were M5x 10mm).
I would recommend giving the 4 contacts that the bolts pass through a good clean before reassembly.
The new 100V cap can now be installed. Makes sure that the positive terminal is located in the right place, and then fix it in place (don't forget the lock washers). Getting the new mounting bolts to bite into the threads on the cap can be a bit fiddly, and you may well find that you have to bend the metal mounting 'frame' that surrounds the caps. I found that holding the whole ECU upright so that the bolts were screwing downwards into the caps was the best way. Once you've got them both to bite, then it should be just a matter of doing them up and then sliding the mounting stud into the slot that you cut.
Installation of the 40V is a little more challenging, as you may have noticed that it is a little longer than the old one that you removed. This is where the next permanent modification comes in - you need to snip off a plastic '+' shaped stud that projects from the front of the mounting frame below the two contacts. Then, with some needle nosed pliers, I bent both the front and rear sections of the mounting frame to make the opening for the cap a bit longer - take it easy with this bit, as you don't want to break any of the legs away from the PCB. Do it little by little, offering up the cap to check if you've got enough space yet.
Once it looks like you've got enough space, now is the time to try and get the small bolts to bite into the contacts on the cap (lock washers!) Once done, then it is a case of tightening them bit by bit, and sliding the mounting stud down into the rear support (you may need to bend the support backwards with the pliers while doing this). Once in, then fully tighten all bolts and nuts on the studs (don't over do it here).
Makes sure there is no debris inside, and then pop the lid on temporarily.
That should be it. Time to give it a try!
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