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Home >> Subaru >> 2005 >> Impreza WRX STi >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Engine (Diagnostics) -- H4DOTC >> Engine Control Module (ECM) I/O Signal >> Electrical Specification
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Electrical Specification

Fig 1: Identifying Engine Control Module Terminals
G03817543Courtesy of SUBARU OF AMERICA, INC.
ENGINE CONTROL MODULE TERMINALS REFERENCE

Content Connector No. Terminal No. Signal (V) Note
Ignition SW ON (Engine OFF) Engine ON (Idling)
Crankshaft position sensor Signal (+) B135 2 0 -7 - +7 Sensor output waveform
Signal (-) B135 11 0 0 -
Shield B135 21 0 0 -
Camshaft position sensor Signal (+) B135 1 0 -1 - +7 Sensor output waveform
Signal (-) B135 10 0 0 -
Shield B135 21 0 0 -
Throttle position sensor Signal B135 7 Fully closed: 0.2 - 1.0
Fully opened: 4.2 - 4.7		 -
Power supply B135 9 5 5 -
GND (sensor) B135 19 0 0 -
Rear oxygen sensor Signal B135 17 0 0 - 0.9 -
Shield B135 26 0 0 -
GND (sensor) B135 19 0 0 -
Front oxygen (A/F) sensor heater Signal 1 B84 5 0-1.0 - Waveform
Signal 2 B84 4 0-1.0 - Waveform
Rear oxygen sensor heater signal B137 13 0-1.0 - Waveform
Engine coolant temperature sensor Signal B135 18 1.0-1.4 1.0-1.4 After warm-up the engine.
GND (sensor) B135 19 0 0 After warm-up the engine.
Vehicle speed signal B134 1 0 or 5 0 or 5 "5" and "0" are repeatedly displayed when vehicle is driven.
Mass air flow sensor Signal B136 13 - 0.3 - 4.5 -
Shield B136 8 0 0 -
GND B136 7 0 0 -
Intake air temperature sensor signal B135 27 0.3 - 4.6 0.3 - 4.6 -
Exhaust temperature sensor Signal B135 16 - 2.7 - 2.8 (750°C) -
GND (sensor) B135 19 0 0 -
Tumble generator valve position sensor RH Signal B135 23 Fully closed: 3.8 - 4.9
Fully opened: 0.2 - 0.9		 -
Power supply B135 9 5 5 -
GND (sensor) B135 19 0 0 -
Tumble generator valve position sensor LH Signal B135 13 Fully closed: 3.8 - 4.9
Fully opened: 0.2 - 0.9		 -
Power supply B135 9 5 5 -
GND (sensor) B135 19 0 0 -
Tumble generator valve RH (open) B136 4 0 or 10 - 13 0 or 13 - 14 Waveform
Tumble generator valve RH (close) B136 5 0 or 10 - 13 0 or 13-14 Waveform
Tumble generator valve LH (open) B136 10 0 or 10 - 13 0 or 13 - 14 Waveform
Tumble generator valve LH (close) B136 11 0 or 10 - 13 0 or 13 - 14 Waveform
Wastegate control solenoid valve B84 24 0 or 10 - 13 0 or 13 - 14 Waveform
Starter switch B134 16 0 0 Cranking: 8 - 14
A/C switch B134 2 ON: 10-13
OFF: 0		 ON: 13-14
OFF: 0		 -
Ignition switch B134 5 10-13 13-14 -
Neutral position switch (MT model) B134 8 ON : 10-13
OFF: 0		 ON: 13-14
OFF: 0		 -
Neutral position switch (AT model) B134 8 ON: 0
OFF: 10-13		 ON: 0
OFF: 13-14		 -
Test mode connector B134 14 5 5 When connected: 0
Knock sensor Signal B135 4 2.8 2.8 -
Shield B135 22 0 0 -
Back-up power supply B84 10 10-13 13-14 Ignition switch "OFF": 10 - 13
Control unit power supply B84 2 10-13 13-14 -
B84 3 10-13 13 - 14 -
Sensor power supply B135 9 5 5 -
Ignition control #1 B137 24 0 13-14 Waveform
#2 B137 23 0 13 - 14 Waveform
#3 B137 22 0 13 - 14 Waveform
#4 B137 21 0 13 - 14 Waveform
Fuel injector #1 B84 1 10 - 13 1-14 Waveform
#2 B137 6 10-13 1-14 Waveform
#3 B137 5 10-13 1-14 Waveform
#4 B137 4 10-13 1-14 Waveform
Idle air control solenoid valve Signal B137 10 0 or 13-14 0 or 13-14 Waveform
Fuel pump control unit Signal 1 B134 13 0 or 5 0 or 5 -
Signal 2 B137 15 10-13 10-13 -
A/C relay control B84 27 ON: 0.5 or less
OFF: 10 - 13		 ON: 0.5 or less
OFF: 13 - 14		 -
Radiator fan relay 1 control B84 17 ON: 0.5 or less
OFF: 10-13		 ON: 0.5 or less
OFF: 13-14		 -
Radiator fan relay 2 control B84 28 ON: 0.5 or less
OFF: 10-13		 ON: 0.5 or less
OFF: 13 - 14		 Model with A/C only
Malfunction indicator light B84 15 - - Light "ON": 1 or less
Light "OFF": 10-14
Engine speed output B137 9 - 0 - 13, or more Waveform
Purge control solenoid valve B84 16 ON: 1 or less
OFF: 10-13		 ON: 1 or less
OFF: 13-14		 Waveform
Manifold absolute pressure sensor Signal B135 8 1.7 - 2.4 1.1 - 1.6 -
Power supply B135 9 5 5
GND (sensor) B135 19 0 0
Fuel tank pressure sensor Signal B135 15 2.3 - 2.7 2.3 - 2.7 The valve operates when fuel filler cap is removed and reinstalled.
GND (sensor) B135 19 0 0 -
Fuel tank pressure control solenoid valve B84 22 ON: 1 or less
OFF: 10-13		 ON: 1 or less
OFF: 13-14		 -
Drain valve B84 11 ON: 1 or less
OFF: 10-13		 ON: 1 or less
OFF: 13 - 14		 -
Fuel tank sensor control valve B84 23 ON: 1 or less
OFF: 10-13		 ON: 1 or less
OFF: 13-14		 -
Fuel level sensor B135 25 0.12 - 4.75 0.12 - 4.75 -
Fuel temperature sensor signal B135 6 2.5 - 3.8 2.5 - 3.8 Ambient temperature: 25°C (75°F)
Blow-by leak diagnosis signal B137 2 0 0 When disconnection (malfunction) = 5
Small light switch B134 17 ON: 0
OFF: 10-13		 ON: 0
OFF: 13-14		 -
Blower fan switch B134 9 ON: 0
OFF: 10 - 13		 ON: 0
OFF: 13 - 14		 -
Rear defogger switch B134 3 ON: 0
OFF: 10-13		 ON: 0
OFF: 13-14		 -
Power steering oil pressure switch B135 24 10 - 13 ON: 0
OFF: 13-14		 -
Front oxygen (A/F) sensor signal (+) B84 29 2.8 - 3.2 2.8 - 3.2 -
Front oxygen (A/F) sensor signal (-) B84 19 2.4 - 2.7 2.4 - 2.7 -
Front oxygen (A/F) sensor shield B84 18 0 0 -
SSM/GST communication line B134 21 Less than 1 <--> More than 4 Less than 1 <--> More than 4 -
Torque control 1 signal B134 19 More than 4 More than 4 -
Torque control 2 signal B134 18 More than 4 More than 4 -
Torque control cut signal B137 14 8 8 -
AT diagnosis input signal B135 20 Less than 1 <--> More than 4 Less than 1 <--> More than 4 Waveform
AT load signal B135 28 4.3 - 4.4 0.9 - 1.4 -
GND (sensors) B135 19 0 0 -
GND (injectors) B137 8 0 0 -
GND (ignition system) B137 18 0 0 -
GND (power supply) B137 17 0 0 -
B134 22 0 0 -
GND (control systems) B134 7 0 0 -
B134 15 0 0 -
GND (front oxygen (A/F) sensor heater 1) B84 9 0 0 -
GND (Front Oxygen (A/F) Sensor heater 2) B84 8 0 0 -
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