Toyota Celica ECU Pinouts ST205 GT4

Toyota Celica ECU Pinouts ST205 GT4


Before the Subaru WRX and the Mitsubishi Evolution became the AWD turbocharged monsters, the Toyota Celica represented what Japan had to offer in the United States. Powered by the robust 3SGTE and a full time AWD system that later shared a lot of similarities with the Mitsubishi Evolution gearbox, the Toyota Celica All-Trac Turbo was an incredible performer.

Originally designed to compete in the World Rally Championships, the Celica All-Trac Turbo became one of the most popular homologation vehicle of the mid 90s. These vehicles were mandated by the sanctioning bodies that all WRC competition vehicles must have road-going versions of themselves.


These Group A cars had several rules and restrictions placed on them to even the playing field, and the Celica became a solid contender in the WRC circuit.

Today we’ll be looking at the ECU pinouts for a 1994 Toyota Celica All-TRAC with the 3SGTE engine in it. If you are swapping a JDM version of the GT4 engine into something, these pins may vary, so be sure to check the color code on each individual ECU pin. Our complete Toyota Celica ECU Pinouts guide will help you install any piggyback or test your ECU for power and signals from the engine’s sensors.


The ECU harness is broken up into 3 groupings which we’ll classify as A, B and C. norm_n1 : sup mang..

Connector A

Pin # Name Label
A1 ECU Ground E01
A3 Injector #1 #10
A4 Injector #2 #20
A5 Injector #3 #30
A6 Injector #4 #40

Connector A

Pin # Name Label
A21 Igniter IGN
A10 Intercooler Relay INT
B12 Idle Switch IDL
A7 ISC Valve RSO

Connector B

Pin # Name Label
B2 Fuel Pump Relay FPR
B8 Knock Sensor KNK
B12 Throttle Position Sensor IDL
B13 Air Intake Temperature THA
B15 Sensor Power VC

Connector C

Pin # Name Label
C21 Battery Power BATT
C22 EFI Main Relay +B

That does it for our Toyota Celica ECU Pinouts article, please let us know if you have any special requests or questions about the engine or ECU harness. Thanks for reading!