{"id":136875,"date":"2025-06-12T08:43:50","date_gmt":"2025-06-12T15:43:50","guid":{"rendered":"https:\/\/www.stevenrhine.com\/?p=136875"},"modified":"2025-08-15T17:47:48","modified_gmt":"2025-08-16T00:47:48","slug":"daihatsu-hijet-89530-87509-89530-87511-transmission-control-unit-tcu-repair","status":"publish","type":"post","link":"https:\/\/www.stevenrhine.com\/?p=136875","title":{"rendered":"Daihatsu Hijet 89530-87509 \/\u00a0 89530-87511 Transmission\u00a0Control Unit (TCU) Repair\u00a0"},"content":{"rendered":"

I don’t see many of the “Tin Can” TCU’s they are a bit more reliable then the Plastic Sealed Daihatsu 89530-87507 86410-2750 TCU’s<\/a>. But they to are also prone to failure due to leaking capacitors.<\/p>\n

Effective: 03\/1\/2026<\/span><\/p>\n

Daihatsu Hijet 89530-87509 \/\u00a0 89530-87511 Transmission\u00a0 Control Unit (TCU) Repair
\n\"Daihatsu<\/a>
\nThis Case is a moderate case, (Top\u00a0 Right\u00a0 Corner) This Will require a little bit of corrosion clean up and some trace repair. I think this one has a good chance of recovery.<\/p>\n

\"Daihatsu<\/a>
\nCapacitor Leakage and Corrosion
\n\"Daihatsu<\/a>
\nAnother Area Of Capacitor Leakage C5 By the Transistors, this is Very mild and the electrolytic leakage appears to not have migrated under the MCU or Corroded away the the transistors\u00a0 you can\u00a0 see it started to attack them.
\n\"Daihatsu<\/a>
\nThe Traces of\u00a0 TR12, TR1, TR10, TR8 “L6” (2SC1623<\/a>) should be inspected at the pad for corrosion. In this case TR1, TR10, TR12 had broken connections and Corrosion Starting on ZD2
\n\"\"<\/a><\/p>\n

These units often require as much time or in some cases, even more\u00a0 to repair than their plastic-encased counterparts that must be physically cut open. This is largely due to the extent of electrolytic corrosion, which can be quite severe and labor-intensive to remediate.<\/p>\n

The most common issues observed include:<\/p>\n

    \n
  1. \n

    Electrolytic Capacitor Leakage<\/strong> \u2013 The primary issue, typically resulting in localized corrosion and conductive residue that must be thoroughly cleaned and neutralized.<\/p>\n<\/li>\n

  2. \n

    Corroded Traces and Vias<\/strong> \u2013 Particularly beneath the EL6004EM and the MCU where electrolyte intrusion from failed capacitors\u00a0 corroders the via and traces<\/p>\n<\/li>\n

  3. \n

    Corroded, Cracked, or Cold Solder Joints \/ Traces on the MCU. <\/strong>If the electrolytic cap next to the MCU leaks it will corrode the traces requiring MCU removal repair of traces and via’s.<\/p>\n<\/li>\n

  4. \n

    Failed Transistors<\/strong> \u2013 In more severe cases, shorted, Corroded or thermally damaged transistors are observed. If visibly burnt, it usually indicates catastrophic failure of the MCU, rendering the unit irreparable as this is a Proprietary Marked Chip. If they are just corroded pad and trace repair is required.<\/p>\n<\/li>\n<\/ol>\n

    Some Photos of this Unit.<\/p>\n

    Primary Corrosion (Area\u00a0 is Wet With\u00a0 Flux) All the black is Corrosion.
    \n    \"Daihatsu<\/a>
    \nUnder IC2 a EL6004EM The Via’s have completely corroded away and will need to be repaired.
    \n    \"\"<\/a> \"\"<\/a>
    \nMain\u00a0 Ground Plane Area By\u00a0 the Capacitors\u00a0 Needs Repaird.
    \n    \"\"<\/a>
    \nCleaning the Corrosion, This is a must you need to use a fiberglass pen and clean.
    \nYou Will Notice the pads have been corroded away and have no contact or minimal contact with their traces.
    \n    \"\"<\/a><\/p>\n

    \"\"<\/a><\/p>\n

    If There is black on the traces the solder mask and conformal coating must be removed to clean this or it will continue to corrode the copper.\"\"<\/a>
    \nBottom of\u00a0 the\u00a0 board vias cleaned.
    \n    \"\"<\/a>
    \nAfter Solder Mask Removal area it tined with solder this is the first round,\u00a0 2nd round gets\u00a0 whats missed.
    \n    \"\"<\/a><\/p>\n

    Repair the vias by filling with a wire, Note: this is a 4 layer PCB the only inner traces I am aware of are at the MCU (IC1) I would like to get one of these and sand it down to map them out but finding one Beyond economical repair that not overly corroded can be used for this would be difficult.\u00a0 X-ray would be ideal for this but there is no one around here with one that is reasonable.<\/p>\n

    Replaced Parts
    \nC7 .01uf 50V Ceramic (Check this capacitor for deterioration and cracks)
    \nC5 \/ C4 10uf 16V (Note: these should be upgraded\u00a0 to 25V for extended life)
    \nC3 3.3uf 50V (Leaked)
    \nC2 1uf 50V (Leaked)
    \nC1 100Uf 50V (Leaked)
    \nR1 47K 1\/8 Watt Carbon (Leads Corroded)
    \nR2 2.7K 1\/8 Watt Carbon (Leads Corroded)
    \nR4 10K\u00a0 (Corroded)<\/p>\n

    Some photos of the repaired unit they are not pretty but all connections have good contact\u00a0 and\u00a0 corroded copper areas have solder build up.
    \n    \"\"<\/a><\/p>\n

    \"\"<\/a>
    \nTransistor\u00a0 pad\u00a0 and trace\u00a0 repair. Be sure to remove the transistors to clean underneath them. Repaired Traces\/Pads At Transistors small magnet wire for jumpers work for the heavily corroded traces with large gaps otherwise a small bridge works. Check\u00a0 continuity with a DMM.
    \n    \"\"<\/a><\/p>\n

    Daihatsu “Tin Can” TCU Repair Pricing<\/strong><\/p>\n