ECU Pinouts (SR20DET)
The following is a description of the major pinouts of the Australian Domestic Market SR20DET S15 ECU.
The Japanese Domestic Market (JDM) pinouts are different as follows:
Pins 30 and 31 are switched
The fuel pump relay is on pin 104 not 106
Diagram
| Pin | Function | Wire | Description |
| 1 | Ignition Signal 1 | R/W | Pulsing between 0 and 3V, should show average 0-0.2V during idle and 0.1-1V at 2000rpm |
| 2 | RPM Signal | L/OR | Approximately average of 1-1.5V while running |
| 3 | Ignition Signal 2 | BR/R | Pulsing between 0 and 3V, should show average 0-0.2V during idle and 0.1-1V at 2000rpm |
| 4 | ECM Relay (Self Shutoff) | R/B | For a few seconds after turning off engine 0-1.5V, then 14V |
| 5 | Ignition Signal 3 | R/G | Pulsing between 0 and 3V, should show average 0-0.2V during idle and 0.1-1V at 2000rpm |
| 6 | ECU Ground | B | 0V - continuous with ground |
| 7 | Data Link Connector | BR/Y | For use with Consult or other diagnostic tool (0V) |
| 9 | Cooling Fan Relay (low) | P/B | 11-14V Engine running without cooling fan; 0V with cooling fan |
| 10 | Cooling Fan Relay (high) | L/G | 11-14V Engine running and fan operating low speed or off; 0-0.6V cooling fan is running at high speed |
| 11 | Air Conditioner Relay | G | A/C and Blower are ON 0-1V; AC switch off 11-14V |
| 12 | Auto Transmission Signal 3 | PU/W | Engine at idle 0-0.1V |
| 13 | ECU Ground | B | 0V - continuous with ground |
| 15 | Data Link Connector | SB | For use with Consult or other diagnostic tool (3-9V) |
| 16 | Mass Airflow Sensor | L | Between 0.8 and 1.5V at idle; between 1.4 and 2.0 at3000rpm |
| 17 | Mass Airflow Sensor Ground | P | 0V - continuous with ground |
| 18 | Water Temperature | P/B | Approximately +5V when ignition switch in ON position (engine not running) |
| 19 | Oxygen (Lambda) Sensor | W | Fluctuating between 0 and 1V when engine is running |
| 20 | Throttle Position Sensor | R | Engine running and throttle fully released
0.15-0.85V; Engine not running and throttle fully pressed 3.5-4.7V |
| 21 | Ground connection for sensors | G/Y | 0V - continuous with ground |
| 23 | Data Link Connector | G/R | For use with Consult or other diagnostic tool (0V) |
| 24 | Malfunction Indicator Lamp | OR | Ignition switch on (0-1V), engine running (11-14V) |
| 25 | Ignition Signal 4 | R/L | Pulsing between 0 and 3V, should show average 0-0.2V during idle and 0.1-1V at 2000rpm |
| 27 | Knock Sensor | W | Engine is running at idle approximately 2.5V |
| 30 | Camshaft Position Sensor Position Signal | B/Y | Alternating between 0 and 5V when engine is running - will appear as about 2.5V when idling and 2.4V at 2000rpm |
| 31 | Camshaft Position Sensor Reference Signal | B/G | Alternating between 0 and 5V when engine is running - will appear as about 0.4-0.8V when idling and 0.6V at 2000rpm |
| 32 | Speed Sensor | W/PU | 2-3V with vehicle moving |
| 33 | Electrical Load Signal | PU or G/R | Electrical load (e.g. window defogger or lights on switch position 2) 11-14V, else 0V |
| 34 | Start Signal | OR/L | Ignition ON 0V; Ignition START 9-12V |
| 35 | Park/Neutral Position Switch | R/G or G/OR | Neutral or park/neutral (A/T) approximately 0V, else 11-14V |
| 36 | Ignition Switch | B/R | Ignition switch off 0V, Ignition switch on 11-14V |
| 37 | Power supply for sensors | LG/R | Ignition switch on, approximately 5V |
| 38 | Power supply for ECU | B/W | 11-14V |
| 39 | Ground for ECU | B | 0V continuous with ground |
| 41 | Air Conditioner Switch | L/B | A/C and blower switch on approximately 0V A/C switch off approximately 5V |
| 43 | Power Steering Oil Pressure Switch | PU/W | Steering wheel fully turned 0V; Steering wheel not turned approximately 5V |
| 44 | Auto Transmission Signal 2 | L/W | Engine at idle 6-8V |
| 45 | Auto Transmission Signal 1 | L/OR | Engine at idle 6-8V |
| 46 | Backup Power supply for ECU | W | 11-14V |
| 47 | Power supply for ECU | B/W | 11-14V |
| 48 | Ground for ECU | B | 0V continuous with ground |
| 101 | Injector Number 1 | W/B | Pulsing at 0 to 40V, average 11-14V |
| 103 | Injector Number 3 | G/B | Pulsing at 0 to 40V, average 11-14V |
| 105 | Intake Valve Timing Control Solenoid | R/L | Idle 11-14V |
| 106 | Fuel Pump Relay | B/P | Ignition ON, immediately 0-1V then to 11-14V after approximately 1 second |
| 107 | ECU Ground | B | Engine Ground |
| 108 | ECU Ground | B | Engine Ground |
| 109 | Backup Power supply for ECU | W | 11-14V |
| 110 | Injector Number 2 | L/R | Pulsing at 0 to 40V, average 11-14V |
| 111 | Oxygen (Lamda) Sensor Heater | B/R | Below 4000rpm 0-1V; above 4000rpm 11-14V |
| 112 | Injector Number 4 | L/B | Pulsing at 0 to 40V, average 11-14V |
| 113 | Idle Air Control Valve | SB | Approx 10-11V |
| 115 | Wastegate Control Solenoid | OR/B | Idle 11-14V |
| 116 | ECU Ground | B | Engine Ground |