Lexus ISF ECU removal procedure
Lexus ISF ECU removal procedure
Before starting this procedure it is recommended that the battery positive terminal is disconnected to avoid damage to any electrical circuits.
Once the battery is disconnected start by removing the front and left side plastic covers in the engine bay. To do this gently push down on the 12 plastic push pins and carefully lift on the panels to lift them from the seated position. Be careful not to loose them as they easily get away from you and fall down into the engine bay. I suggest starting from the airbox side and working your way around to the brake fluid reservoir.
There is also a 12 mm plastic nut between the engine cover and the left strut tower that you can unscrew with a socket or just lift up on.
Once you have the panels removed you will have access to the ECU housing located just behind the left headlamp.
Remove the (3) 10mm bolts and remove the cover.
You will now have to unplug 3 connectors and unclip 3 others that are overlaying the ECU to allow access.
Remove in the following order:
White 2 wire connect- push tab and pull on this connection to remove.
Large connected with black latch- push in on tab and lift up on the forward end of the latch.
Blue connection at rear left-
push tab and pull on this connection to remove.
Now to remove the 3 remaining connectors with the blue terminating ends from the clips that seat them to the large white plastic organizer.
You will use a pick or a small flat screwdriver to lift the tooth that holds them to the white plastic part and carefully lift them away.
Once this is done you will then do the same to the one tooth at the rear outside corner that is holding the white plastic part in place and lift that way as well.
Now you have access to the (6) plugs for the ECU that you will remove by pushing in on the tabs and carefully lifting away.
You can now unclip the black plastic guide on the rear harness located at the front of the strut tower and the carefully lift up on the guides for the two rubber wire harness bellows
going in to the ECU housing.
If you have a rear O2 sensor simulator now will be the time to move that out of the way.
The last connector you have to remove is the rear of the two black plugs going in to the module next to the ECU.
Once all if this is done you can move all of the wiring away from the ECU.
Now remove the (2) 10mm nuts on either end of the ECU, lift it out of the box and you're done!
Once the battery is disconnected start by removing the front and left side plastic covers in the engine bay. To do this gently push down on the 12 plastic push pins and carefully lift on the panels to lift them from the seated position. Be careful not to loose them as they easily get away from you and fall down into the engine bay. I suggest starting from the airbox side and working your way around to the brake fluid reservoir.
There is also a 12 mm plastic nut between the engine cover and the left strut tower that you can unscrew with a socket or just lift up on.
Once you have the panels removed you will have access to the ECU housing located just behind the left headlamp.
Remove the (3) 10mm bolts and remove the cover.
You will now have to unplug 3 connectors and unclip 3 others that are overlaying the ECU to allow access.
Remove in the following order:
White 2 wire connect- push tab and pull on this connection to remove.
Large connected with black latch- push in on tab and lift up on the forward end of the latch.
Blue connection at rear left-
push tab and pull on this connection to remove.
Now to remove the 3 remaining connectors with the blue terminating ends from the clips that seat them to the large white plastic organizer.
You will use a pick or a small flat screwdriver to lift the tooth that holds them to the white plastic part and carefully lift them away.
Once this is done you will then do the same to the one tooth at the rear outside corner that is holding the white plastic part in place and lift that way as well.
Now you have access to the (6) plugs for the ECU that you will remove by pushing in on the tabs and carefully lifting away.
You can now unclip the black plastic guide on the rear harness located at the front of the strut tower and the carefully lift up on the guides for the two rubber wire harness bellows
going in to the ECU housing.
If you have a rear O2 sensor simulator now will be the time to move that out of the way.
The last connector you have to remove is the rear of the two black plugs going in to the module next to the ECU.
Once all if this is done you can move all of the wiring away from the ECU.
Now remove the (2) 10mm nuts on either end of the ECU, lift it out of the box and you're done!
Last edited by RCB; Jan 21, 2016 at 06:45 AM.
soon ?
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Top man Chris. 
Very helpful indeed given what's occurring with the RR-Racing tune!
Be fun to see how many visitors come here in the next few months! Lol.
Top effort and great community spirit that man!
Very helpful indeed given what's occurring with the RR-Racing tune!
Be fun to see how many visitors come here in the next few months! Lol.
Top effort and great community spirit that man!
Very nice, thank you, now I don't have to do it!
I will say that I actually don't bother fully removing the upper blue connectors... you can wedge that out of the way and then pull the ecu out.
For the nuts that hold the ecu in place, its nice to have a magnet to pic those up so they don't fall in the box.
Rafi
I will say that I actually don't bother fully removing the upper blue connectors... you can wedge that out of the way and then pull the ecu out.
For the nuts that hold the ecu in place, its nice to have a magnet to pic those up so they don't fall in the box.
Rafi
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I did add every last detail for the guys that are not mechanicly inclined but there are a few steps that you can skip if you're comfortable with this stuff and know your not going to snap anything plastic.
I don't pull the front plastic engine bay panel but rather lift it and slip the left side panel out and as Rafi said you can skip the upper blue connector as well as the final black plug.
Just be careful guys, the last thing you want is hacked up looking connectors, broken clips or wires pulled from the connectors, especially if you're in warranty.
I don't pull the front plastic engine bay panel but rather lift it and slip the left side panel out and as Rafi said you can skip the upper blue connector as well as the final black plug.
Just be careful guys, the last thing you want is hacked up looking connectors, broken clips or wires pulled from the connectors, especially if you're in warranty.
