How To Replace Transmission Control Unit In 1991 Honda Accord

Want to know how to replace transmission control unit In 1991 Honda Accord?  Replacing the transmission control in a Honda Accord can be a chore. The main cause of the transmission control unit (TCU) to fail is the capacitors inside leak over time causing a short. The car then is forced in to 'limp' mode which restricts the normal rev range and the car holds back.

The common problems of needing to replace the transmission control unit on a 1991 Honda Accord are:

  1. The car will not change out of second gear.
  2. The clutch will slip when the gear is in D4.
  3. The dashboard light, labeled 'sport' stays on.

To replace the transmission control in a Honda Accord you will want to follow these steps.


  • A rebuilt TCU
  • Deep sockets and a ratchet


  1. In the passenger side foot-well, un-clip the carpet at the side near to the door, these pop clips come off. Pull the carpet so you can see the bare metal floor of your Honda Accord.
  2. Where the passenger puts their feet, there is a kick-plate. Remove the six retaining screws. Remove the plate and you will see the ECU and the TCU. Remove the four nuts of the TCU with a 10mm deep socket.
  3. Un-clip the electrical connectors which are attached to the TCU. Remove it from the car. Some auto shops will take the TCU as an exchange for a rebuilt one, or you could rebuild the unit yourself using new capacitors and clean the terminals inside with rubbing alcohol to get the gunk off from the old capacitors.
  4. Fit the new TCU to the mounting holes, and tighten the screws in. Hook up the electrical connectors, they only go in one way so don't force it.
  5. Replace the kick plate and all six retaining screws. Refit the carpet, making sure all of the pop clips snap back into place to keep the carpet snug.
  6. Disconnect the negative battery lead and leave it off for a few minutes. This resets the ECU. Refit and start up the car. Select each gear on the test drive to make sure they all work in different conditions.
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