ECU connector pinout for the 1987–1988 Toyota Supra MA70 with 7M-GE or 7M-GTE engine, covering EFI, ESA, and self-diagnosis via TCCS.
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ECU - Electronic Control Unit Connector.
The 1987–1988 Toyota Supra MA70 uses Toyota’s TCCS (Toyota Computer Controlled System) ECU to govern EFI (Electronic Fuel Injection), ESA (Electronic Spark Advance), and on-board self-diagnosis. Two engine variants were offered: the 7M-GE (3.0 L DOHC naturally aspirated) and the 7M-GTE (3.0 L DOHC turbocharged). The ECU connects via three multi-pin waterproof connectors (A, B, C); integrated-circuit terminals are extremely sensitive to electrostatic discharge and the ECU cover must not be opened. Diagnostic trouble codes are read via the CHECK ENGINE warning light by shorting the T (7M-GE) or TE1 (7M-GTE) terminal to E1 on the check connector.
Connector A
Pin
name
Signal
1A
Power Ground
Ground
2A
Injectors 1 & 4
Speed
7A
Injectors 2 & 6
Speed
8A
Injectors 3 & 5
Speed
9A
Computer Ground
Ground
Connector B
Pin
name
Signal
9B
Water Temperature Sensor
Analog
14B
Throttle Position Sensor
Analog
Connector C
Pin
name
Signal
1C
O2 Sensor
Analog
6C
Speedometer
Speed
8C
Intake Air Temperature Sensor
Analog
10C
Air Flow Meter
Analog
Notes
The ECU uses three separate waterproof connectors (A, B, C); never probe terminals directly — use the designated check sub-harness or a circuit tester with the approved check connector terminals.
The check connector exposes terminals T/TE1 and E1. Shorting T (7M-GE designation MA) or TE1 (7M-GTE designation MS) to E1 initiates diagnostic code output via the CHECK ENGINE light using 0.25-second blink pulses.
Fuel pump circuit can be activated for testing via the +B and FP terminals on the check connector; terminal IGO is also present.
IC components inside the ECU are extremely sensitive to static electricity; do not open the ECU cover under any circumstances.
The TCCS ECU controls EFI (fuel injection), ESA (ignition timing advance), and self-diagnosis on both engine variants.
Signals
Power Ground (1A) — main power ground for the ECU and actuator circuits.
Injectors 1 & 4 (2A) — fuel injector drive signal for cylinders 1 and 4.
Injectors 2 & 6 (7A) — fuel injector drive signal for cylinders 2 and 6.
Injectors 3 & 5 (8A) — fuel injector drive signal for cylinders 3 and 5.
Computer Ground (9A) — dedicated signal ground reference for ECU logic circuits.
Water Temperature Sensor (9B) — analogue voltage signal from the coolant temperature sensor (THW); used by the ECU for cold-start enrichment and timing correction.
Throttle Position Sensor (14B) — analogue voltage (VTA) from the throttle position sensor; signals throttle angle for fuel and timing calculations.
O2 Sensor (1C) — analogue feedback signal from the exhaust oxygen sensor; used for closed-loop fuel trim.
Speedometer (6C) — vehicle speed pulse signal from the speedometer sensor; used by the ECU for speed-density and idle-up calculations.
Intake Air Temperature Sensor (8C) — analogue voltage (THA) from the intake air temperature sensor; used for air-density fuel correction.
Air Flow Meter (10C) — analogue voltage from the vane-type air flow meter (VS signal); primary load input to the ECU for fuel injection quantity calculation.
ECU - Electronic Control Unit Connector.