4TH gen GT GTS All-Trac 3sgte upgrade

Harness Connectors Firewall End Of Engine Harness



Above is a list of various plugs and harness connectors that connect a 3sge engine wiring
harness to the rest of the car. These are the connections that your new engine will have to
connect to. Below is a detailed look at how various wires and plugs were traced and other
considerations that need to be made when upgrading to a 3sgte.

So you got a 4th gen and you want to stuff a bit more power in it with a 3sgte.

What you need
-3sgte
-3sgte engine wiring harness and all the sensors/electronics that connect to it
(afm/maf, coil, igniter, AC sensors, O2 sensors, water temp, oil pressure, ECU........ )
-all intercooler bits
-downpipe

If your starting with a GT or All-Trac your good to go
If you have a GTS your starter is probably going to be under the exhaust manifold
where the new turbo is going to be so your going to need to modify your tranny
to accept a GT or All-Trac starter and you will also need the clutch and flywheel
from the GT or All-Trac, you can also find the clutch flywheel and starter on camry's.
Other option is to replace the tranny with a GT or camry tranny once again you will
also need the clutch flywheel and starter.

So now your ready to get going. Right now you should be looking at a 3sgte engine
wiring harness that has all its plugs connected to bits you got with the engine except
for a few plugs at one end of the harness that connect to the battery and engine bay
fuse box. The following picture shows a 4th gen 3sge engine wiring harness battery end.
You will need to take some of these plugs and splice them into your 3sgte harness so
your 3sgte harness can plug into the 4th gen engine bay fuse box.


2B, 2C, 2G, 2H are the only plugs you should need from your old 3sfe,3sge engine wiring harness, all the other plugs ont the engine wiring
harness are engine related the only exception I can think of is 2 plugs for the tranny for a speed sensor and reverse indicator.


If you got an ST165 engine to install your good to go its all just plug and play. The ST165 3sgte engine wiring harness has plugs 2B, 2C, 2G, 2H
allready on it so you don't have to splice anything just plug the ST165 engine wiring harness into the 4th gen engine bay fuse box. You may
have to wire up the intercooler pump as I'm not sure if its on the engine wiring harness or engine bay wiring harness but other than that putting
in an ST165 engine is going to be the easiest.

If you want to put in an ST185, ST205, ST215 engine your going to have to modify the new engine wiring harness to plug into the 4th gen engine
bay fuse box. These should be the only connections on you new harness that don't connect to a part of your new engine or electronic bits that
came with the engine. So we have to look at the 4th gen engine bay fuse box


It does not matter if you have a GT GTS or All-Trac all the fuse boxes are the same. GT & All-Trac fuseboxes are identical GTS fuse boxes look
slightly different but all the plugs/locations are the same. Heres whats going on inside the fusebox.


So what we need to do is identify what the wires for the 4 plugs are for
Plug 2B




Plug 2C




Plug 2G




Now that we know what the plugs and wire colors are we need to check the electrical diagrams
to see what the wires do.


closeup



In this case I'm going to start looking at
Plug 2B
Pin 1 red - 12 volts coming out of the fuseable link box
Pin 2 white - 12 volt 40 amp AM1 fuseable link
Pin 3 white - 12 volt 40 amp AM1 fuseable link
Pin 4 black with red stripe - 12 volt 30 amp AM2 fuseable link
Pin 6 yellow - "L" terminal of the altenator






Plug 2C
Pin 1 green with black stripe - A/C high pressure switch(radiator fan) 3sge
Pin 3 white with black stripe - circuit opening relay pin6, air flow meter pin 2, vsv(for engine idle up) pin 1, cruise control vacuum pump,
cruise control vacuum switch, cruise control switch(comb. sw)
Pin 4 green with black stripe -
Pin 6 black with white stripe - A/C magnetic clutch

Plug 2G
Pin 2 pink - TCCS ECU pin 2
Pin 3 black with orange stripe - plug 2G pin 6
Pin 4 yellow - charge warning light (combination meter)
Pin 5 black with yellow stripe - circuit opening relay pin 2, TCCS ECU pin 14, TCCS ECU pin 13,check connector pin 12, oxygen sensor pin 2, vsv (for T-vis) pin 2
Pin 6 black with orange stripe - plug 2G pin 3

Plug 2H
Pin 1 white - 12 volt 40 amp AM1 fuseable link


With all that being said there is one more thing to consider. If you get a JDM engine the engine wiring harness will be for a
right hand drive car. Its going to want to have the part of the harness that goes to the ECU go through the firewall on the
drivers side not near the windshield wiper motor on the passenger side so just one more problem to solve


That should get you a running engine, later I'll look at some extra's that would be nice to have like hooking up the sensors
in the engine to the instrument cluster.

 

I've updated the listing for the 4 plugs that connect to the engine bay main fusebox

color green indicates the plug number and pin number
color black indicates what the wire connects to once it leaves the fusebox
color red indicates what the internal connection is within the fusebox

Plug 2B
Pin 1 red - 12 volts coming out of the fuseable link box
--- headlight relay pin 3
Pin 2 white - 12 volt 40 amp AM1 fuseable link
--- plug 2D pin 1
Pin 3 white - 12 volt 40 amp AM1 fuseable link
--- plug 2F pin 1
Pin 4 black with red stripe - 12 volt 30 amp AM2 fuseable link
--- plug 2F pin 4
Pin 6 yellow - "L" terminal of the altenator
--- 7.5A charge fuse

Plug 2C
Pin 1 green with black stripe - A/C high pressure switch(radiator fan) 3sge
--- plug 2A pin 1
Pin 3 white with black stripe - circuit opening relay pin6, air flow meter pin 2, vsv(for engine idle up) pin 1, cruise control vacuum pump,
cruise control vacuum switch, cruise control switch(comb. sw)
--- EFI main relay pin 3, plug 2E pin 5, engine main relay pin 3, engine main relay pin 2, plug 2A pin 7
Pin 4 green with black stripe - radiator fan water temp switch
--- plug 2E pin 2, radiator fan relay no 1 pin 2, plug 2A pin 8
Pin 6 black with white stripe - A/C magnetic clutch
--- plug 2E pin 6

Plug 2G
Pin 2 pink - TCCS ECU pin 2
--- EFI main relay pin 4, 15A EFI
Pin 3 black with orange stripe - plug 2G pin 6
--- plug 2E pin 1, radiator fan relay no 1 pin 1, engine main relay pin 1
Pin 4 yellow - charge warning light (combination meter)
--- 7.5A charge
Pin 5 black with yellow stripe - circuit opening relay pin 2, TCCS ECU pin 14, TCCS ECU pin 13,check connector pin 12, oxygen sensor pin 2, vsv (for T-vis) pin 2
--- EFI main relay pin 2
Pin 6 black with orange stripe - plug 2G pin 3
--- EFI main relay pin 1

Plug 2H
Pin 1 white - 12 volt 40 amp AM1 fuseable link
--- engine main relay pin 5

As I said before I still have to do the wiring for the instrument cluster, I would have thought they would have gone
through on the drivers side but I guess their all taking the long route. I did say before that at this point you should
be able to start the motor but I have noticed that the starter wire is not included in one of the 4 plugs so I'll have
to track that one down as well although technically you could jump the starter and get the engine running

 

Looking at the other end of the engine harness just before it goes through the firewall their are
2 connectors that join to other wiring harnesses. Their identified as connectors C1 & C2


At the end of the harness are several more plugs most go to the ECU one goes to the circuit
opening relay and G1 is a connector to another wiring harness


G1

pin 1 blue with white stripe - TCCS ECU pin 7
--- speed sensor (comb. meter) pin 1
pin 2 black with yellow stripe - altenator pin 3
--- 10A engine fuse
pin 3 yellow - 7.5A charge fuse pin 4
--- charge warning light (comb. meter)
pin 4 yellow with green stripe - water temp sender
--- water temp guage pin 3
pin 8 red with blue stripe - back up light switch pin 2
--- 15A guage fuse pin 2
pin 9 red with black stripe - back up light switch pin 1
--- back up lights pin 2

G1

pin 10 blue with black stripe - check connector pin 1 (FP)
--- fuel pump pin 1, circuit opening relay pin 1
pin 11 orange - diode (electrical idle up) pin 2
--- TCCS ECU ISCV (3sge), VSV (engine idle up) (3sge), TCCS ECU ELS (3sgte)
pin 12 yellow with black stripe - oil pressure switch
--- oil pressure guage pin 2
pin 13 green - TCCS ECU pin 19
--- chechk engine (comb. meter)
pin 16 black - igniter pin 6
--- tachometer pin 4
pin 17 brown - ground
--- water temp pin 6

C2

pin 1 black - starter, circuit opening relay pin 3, TCCS ECU pin 3(STA), TCCS ECU pin 1(NSW)
--- starter relay pin 2
pin 2 black with orange stripe - ignition coil pin 1, igniter pin 3, noise filter pin 1, injectors 1 2 3 4 pin 2,
--- ignition switch IG2 pin 7
pin 4 white - 40A AM1
--- 30A heater CB

C1

pin 1 white with blue stripe - A/C compressor sensor pin 2
--- A/C amplifier pin 16
pin 2 blue - speed sensor pin 1
--- cruise control computer pin 7
pin 3 green with red stripe - stop light switch
--- TCCS ECU pin 6
pin 4 white with red stripe - A/C compressor sensor pin 1
--- A/C amplifier pin 9, A/C thermistor pin 1
pin 5 black - igniter pin 4
--- A/C amplifier pin 10
pin 6 brown - speed sensor pin 2
--- cruise control computer pin 13



That should take care of all the connections(plugs) on the engine wiring harness that don't connect dirrectly to the engine
or one of its electrical components. I'll try to clean it all up a bit and post some additional relevant info