ECU connector pinout for the 1993–1995 Toyota MR2 Turbo (SW20, 3S-GTE), covering TCCS engine management multi-connector terminals.
Your support helps keep this website running. Please consider supporting this project. SPONSORDONATE
Updated:
ECU - Electronic Control Unit Connector.
The 1993–1995 Toyota MR2 Turbo (SW20, revisions 3–5) uses a Toyota Computer Controlled System (TCCS) ECU paired with a 2.0-litre DOHC 16-valve turbocharged 3S-GTE engine. The TCCS unit governs Sequential Fuel Injection (SFI), Electronic Spark Advance (ESA), and on-board self-diagnostics. The ECU connects via multiple waterproof connectors; terminal measurement requires a check sub-harness SST to avoid damaging the sealed pins. Diagnostic trouble codes are read by shorting the TE1 and E1 terminals on the check connector and counting CHECK ENGINE light blink sequences.
Connector A
Pin
name
Signal
A20
Ignition Control Module
RPM
A26
Power Ground
Ground
Connector B
Pin
name
Signal
B3
Intake Air Temperature Sensor
Analog
B4
Engine Coolant Temperature Sensor
Analog
B5
MAP Sensor
Analog
B6
Primary O2 Sensor
Analog
B11
Throttle Position Sensor
Analog
Connector D
Pin
name
Signal
D4
Brake Switch
Analog
D9
Vehicle Speed Sensor
Speed
Signals
A20 — Ignition timing signal (RPM) output from the ECU to the ignition control module; used by TCCS for Electronic Spark Advance (ESA).
A26 — Power ground; ECU chassis earth reference.
B3 — Intake Air Temperature (THA) sensor; analogue voltage input indicating inlet air temperature to the TCCS.
B4 — Engine Coolant Temperature (THW) sensor; analogue voltage input used for fuel enrichment, fan control, and diagnostics.
B5 — Manifold Absolute Pressure (MAP) sensor; analogue input for load calculation on the 3S-GTE.
B6 — Primary oxygen (O2) sensor; analogue feedback signal for closed-loop fuel correction.
B11 — Throttle Position Sensor (VTA); analogue voltage proportional to throttle opening angle.
D4 — Brake switch input; signals the ECU when the brake pedal is depressed.
D9 — Vehicle Speed Sensor (SPD); pulse signal used by the TCCS for speed-dependent fuelling and diagnostics.
Notes
The ECU connectors are waterproof; use the appropriate check sub-harness SST for terminal voltage measurement — probing pins directly risks damaging the seals and connector lock mechanisms.
On-board diagnostics (OBD1): short terminals TE1 and E1 on the check connector to enter diagnostic mode; trouble codes are output as CHECK ENGINE warning light blink sequences (0.25-second pulses per digit, 1.5-second pause between digits, 2.5-second pause between codes).
The TCCS ECU reference voltage (VC) is 4.5–5.5 V; battery voltage at the BATT terminal should read 9–14 V with the ignition on.
IC components inside the ECU are sensitive to electrostatic discharge; do not open the ECU cover or probe internal circuits.
The 1993 MR2 Electrical Wiring Diagram (EWD) documents ECU relay locations and engine control circuit routing for the SW20/SW21 series.
ECU - Electronic Control Unit Connector.