Hi,
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I couldn't find any info on this, so I thought I let you all know what capacitors are in the power steering ECU(s).
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As we
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(should) replace all the capacitors in the main ECU, the power steering system shouldn't be treated otherwise.
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This guide covers:
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89650-17081 PS Computer from 07.1994 to 1999
89652-17011 PS Motor driver from 1989 to 1999
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(according to my quick research)
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This is not a comprehensive guide, I won't go into details how to solder and stuff.
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Its a pretty easy solder job as the boards are only double sided, but be sure this is not your first solder job ever.
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You can rip VIAs out
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(interconnects between the two sides) and do other damage as well.
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You need to remove the spare wheel, the plastic lining and the metal cage which supports the plastic lining
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(Yellow arrow) from the frunk.
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Tools for removal: Flat head screwdriver, 10 and 12mm sockets
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Starting with the computer
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(black plastic box), Remove the connector bracket
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(White arrow), Pry the box out which held by 3 clips
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(Blue arrows), Remove rubber boot and disconnect the box.
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![Image](https://i.imgur.com/vSoZ4Vnh.jpg)
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This is inside:
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![Image](https://i.imgur.com/V4pqSdTh.jpg)
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The aluminium electrolytic capacitors are:
C3
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- 50V
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2.2uF
C6
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- 50V
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10uF
C11
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- 50V
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4.7uF
C18
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- 50V
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4.7uF
C21
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- 16V
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47uF
C29
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- 50V
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47uF
C34
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- 16V
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47uF
C32
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- 50V
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47uF
C30
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- 16V
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47uF
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Replace them all with at least 105C temperature rated good quality capacitors
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(Just to name a few: Panasonic, Rubycon, Nichicon, Nippon chemicon) I usually use low ESR panasonics.
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Anyways, below is the reason you might consider doing this
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(Corrosion due to leaking electrolyte in my board form 1995)
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![Image](https://i.imgur.com/37zqICJh.jpg)
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Moving on: Motor Driver
Disconnect the top electrical connector, remove the 3 screws
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(1st picture, Green arrows), lift out the box and you can easily disconnect the two remaining electrical connectors.
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Remove all the screws on the box, except the 2x2 screws on the left side holding the 2 brackets.
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This is inside:
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![Image](https://i.imgur.com/IxvNGLLh.jpg?1)
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Undo the marked screws to remove the board.
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The rubber grommet slides out with the board and cables.
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Once removed, try not to put much stress on the cables, you don't want to weaken/crack the solder joints.
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![Image](https://i.imgur.com/wZJr2Jlh.jpg)
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The aluminium electrolytic capacitors are:
C1
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- 50V 47uF
C3
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- 50V 47uF
C16
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- 50V 10uF
C25
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- 50V 1uF
C26
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- 50V 1uF
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Replace them all with at least 105C temperature rated good quality capacitors
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(Just to name a few: Panasonic, Rubycon, Nichicon, Nippon chemicon)
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The white paste on the underside is thermally conductive as the housing is the heatsink for the MOSFETs.
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You may change it or leave it, but don't wipe it off and assemble it without any paste.
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Notes:
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- I didn't measure capacitor diameter, height or lead spacing, usual size capacitors will do just fine here.
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Plenty of space around all components.
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- You may also look around for cracked solder joints on both boards and re-solder if necessery.
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I found a few fishy ones in the PS ECU and a few cracked joints in my light retractor module
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![Image](https://i.imgur.com/pTkc9ibh.jpg)
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- You may also support the newly installed caps with some glue, so their weight will not crack the joints due to vibration.
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I used hot glue sticks for this purpose.
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All you need is a small amount to connect the capacitors body to the PCB.
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Don't pot the board
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- You can use higher voltage rated capacitors if only that's what you have in stock.
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Don't use lower voltage rated ones.
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This doesn't apply to the capacity rating, use the correct capacitance.
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Hope it helps
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Cheers