AEM Series 2 Plug Play EMS 306821 User Manual

							Page 11 of 21 
Troubleshooting Operational Faults 
 
Should an operational fault be detected, please read and follow the following suggestions for each 
system. 
 
APP 
 Ensure the accelerator pedal position sensor is in good condition and plugged in. 
 Double-check that APP sensor is wired per OEM specifications. 
 Check all wiring for shorts or intermittent connections. 
 
TPSA/TPSB 
 Ensure the throttle position sensor is in good condition and plugged in. 
 Double-check that throttle body/TPS sensor is wired per OEM specifications. 
 Check all wiring for shorts or intermittent connections. 
 
Target 
 Ensure throttle body bore is clean and free from obstruction. 
 Ensure vehicle battery is in good condition and properly charged. 
 
System Voltage 
 Ensure vehicle battery is in good condition and properly charged. 
 Check all wiring for shorts or intermittent connections. 
 
Motor Driver 
 Double-check that throttle body/TPS sensor is wired per OEM specifications. 
 Check throttle body wiring for shorts or intermittent connections. 
 Ensure EMS has not been installed in an area of extreme heat ( > 120°C) 
 
WDR 
 Contact AEM EMS Technical Support 
 
EEPROM 
 Perform ETC system calibration 
 Restore ETC system factory calibration 
 Contact AEM EMS Technical Support 
 
  
						

							Page 12 of 21 
 
 
Wiring accessories to the EMS 
Please  follow  this  suggested  wiring  diagram  when  adding new accessories and  retaining 
original  accessories such  as  the multiplex  coolant  temperature  gauge,  air  conditioning 
switch, reverse lockout, UEGO gauges, MAP sensors, IAT sensors, or switches for use with 
the EMS. Note that wire polarity is not important for the Air Temperature sensor.   
 
 
30-1820 (Series 1) vs 30-6820 (Series 2) EMS differences: 
The EMS functions assigned to certain pins have been changed and no longer match the 30-
1820 EMS. Unless otherwise noted, the following pins and functions will need to be manually 
reconfigured after using AEMTuner to convert a 30-1820 Series1 EMS calibration for use 
with the 30-6820 Series 2 hardware. 
Pin  Vehicle harness destination 30-1820 function 30-6820 function Notes 
A2 Front O2 sensor heater Injector #5 --- Injector 5 moved to pin C2 
A3 Front O2 sensor heater Injector #6 --- Injector 6 moved to pin C1 
A4 --- --- Sensor Ground Additional spare output 
A5 --- --- O2 #1 Additional spare output 
B13 --- --- Coil 6  Additional spare output 
B14 --- --- Coil 5 Additional spare output 
B15 Ignition Control #4 Coil #5 Coil 4 Calibration must be updated 
B26 Fuel Pump Control Idle #1/2 Coil 8, LS 12 See ‘Fuel Pump Control’ on page 3  
B28 --- --- CANH  
B29 --- --- CANL  
B34 --- --- HS1  
C1 --- --- Injector 6  
C2 --- --- Injector 5  
C24 --- --- Knock 2 Additional spare input 
D17 Main Relay control FM Coil 7 Use Coil7 settings in AEM startup cal +5V Sensor Power (tapped)
Sensor Ground (tapped)
MAP Signal
Sensor Ground (tapped)
O2 Sensor 1
Black (Sensor Ground)
Green (MAP Signal)
Red (+5V Sensor Power)
Black (Battery or chassis ground)
Red (+12V power, 5A fuse)
AEM UEGO P/N: 30-5130
Brown (Analog - signal)
White (0-5V Analog + signal)Pink (Switched +12V Power)
MAP Sensor P/N: 30-2130-50
A5
A4, C31, or C35 
A4, C31, or C35 
C16
C22
IAT Sensor
Sensor Ground (tapped)Air Temperature Sensor P/N: 30-2010A4, C31, C35
C13
Switch connects to GND
Ground
Switch 2 InputC9
AEM EMS P/N: 30-6820 or 30-6821  
						

							Page 13 of 21 
1) Install AEMTuner software onto your PC  
The latest version of the AEMTuner software can be downloaded from the AEMTuner 
section of the AEM Performance Electronics forums found at www.aemelectronics.com  
Series 2 units are not supported by the older AEMPro tuning software.  
 
2) Remove the Stock Engine Control Unit 
a) Disconnect negative terminal from battery 
b) Access the stock Engine Control Unit (ECU). The location of the ECU on the WRX is 
underneath the passenger side floorboard. A 10mm socket is required to remove the 
kick panel that covers the stock ECU.  
c) Carefully  disconnect  the  wiring  harness  from  the  ECU.  Avoid  excessive  stress  or 
pulling  on  the  wires,  as  this may  damage  the  wiring  harness. All connectors must be 
removed  without  damage  to  work  properly  with  the  AEM  ECU.  Do  not  cut  any  of  the 
wires in the factory wiring harness to remove them.  
d) Remove the fasteners securing the ECU to the car body, and set them aside. Do not 
destroy  or  discard  the original ECU,  as  it  can  be  reinstalled  easily  for  street  use  and 
troubleshooting. 
 
3) Install the AEM Engine Management System 
a) Plug the factory wiring harness into the AEM EMS and position it so the wires are not 
pulled  tight  or  stressed  in  any  manner.  Secure  the  EMS  with  the  provided  Velcro 
fasteners. 
b) Reconnect the negative battery terminal. 
c) Plug the communications cable into the EMS and into your PC. 
d) Turn the ignition on, but do not attempt to start the engine.  
e) At the time these instructions were written, new EMS units do not require USB drivers 
to  be  installed  on  the  PC.  The  EMS  will  automatically be  detected as  a  human 
interface device (HID). 
f) With the AEMTuner software open, select ECU>>Upload Calibration to upload the 
startup calibration file (.cal) that most closely matches the vehicle’s configuration to 
be tuned. Check the Notes section of the calibration for more info about the vehicle it 
was configured for. These files can be found in the following folder:  
C:\Program Files\AEM\AEMTuner\Calibrations\AEM Updates\Subaru\  
g) Set the throttle range: Select Wizards>>Set Throttle Range and follow the on-screen 
instructions. When finished, check that the ‘Throttle’ channel never indicates less 
than 0.2% or greater than 99.8%, this is considered a sensor error and may cause 
some functions including idle feedback and acceleration fuel to operate incorrectly.   
						

							Page 14 of 21 
 
4) Ready to begin tuning the vehicle. 
a) Before  starting  the  engine,  verify  that  the  fuel  pump  runs  for  a  couple  of  seconds 
when the key is turned on and there is sufficient pressure at the fuel rail.  
If  a  MAP  sensor  is  installed,  check  that  the  Engine  Load  indicates  something  near 
atmospheric  pressure  (approximately  101kPa  or  0  PSI  at  sea  level)  with  the  key  on 
and  engine  off.  Press  the  throttle  and  verify  that  the  ‘Throttle’  channel  responds  but 
the Engine Load channel continues to measure atmospheric pressure correctly.  
 
 
b) Start the engine and make whatever adjustments may be needed to sustain a safe 
and reasonably smooth idle. Verify the ignition timing: Select Wizards>>Ignition 
Timing Sync from the pull-down menu.  Click the ‘Lock Ignition Timing’ checkbox 
and set the timing to a safe and convenient value (for instance, 10 degrees BTDC). 
Use a timing light to compare the physical timing numbers to the timing value you 
selected. Use the Sync Adjustment Increase/Decrease buttons to make the physical 
reading match the timing number you selected. 
 
Crankshaft timing marks are not labeled for some vehicles. Consult the factory 
service manual for more information. 
 
 
c) Note:  This  calibration  needs  to  be  properly  tuned  before  driving  the  vehicle.  It  is 
intended for racing vehicles and may not operate smoothly at idle or part-throttle.  
 
 
 
NEVER TUNE THE VEHICLE WHILE DRIVING  
						

							Page 15 of 21 
 
5) Troubleshooting an engine that will not start 
a) Double-check  all  the  basics  first. Engines  need  air,  fuel,  compression,  and  a 
correctly-timed  spark  event.  If  any  of  these  are  lacking,  we  suggest checking  simple 
things  first.  Depending  on  the  symptoms,  it  may  be  best  to  inspect  fuses,  sufficient 
battery  voltage,  properly  mated  wiring  connectors,  spark  using  a  timing  light  or  by 
removing  the  spark  plug,  wiring  continuity  tests,  measure  ECU  pinout  voltages, 
replace recently-added or untested components with known-good spares. Check that 
all EMS sensor inputs measure realistic temperature and/or pressure values.  
 
b) If  the  EMS  is not firing  the  coils  or injectors at  all,  open  the  Start tab  and  look for the 
‘Stat  Sync’d’  channel  to  turn  ON  when  cranking.  This  indicates  that  the  EMS  has 
detected  the  expected  cam  and  crank  signals;    if  Stat  Sync’d  does  not  turn  on, 
monitor  the  Crank  Tooth  Period  and  T2PER  channels  which  indicate  the  time 
between  pulses  on  the  Crank  and  T2  (Cam)  signals.  Both  of  these  channels  should 
respond  when  the  engine  is  cranking,  if  either  signal  is  not  being  detected  or 
measuring  an  incorrect  number  of  pulses  per  engine  cycle  the  EMS  will  not  fire  the 
coils or injectors. 
 
c) If  the  Engine  Load  changes  when  the  throttle  is  pressed  this  usually  indicates  that 
there is a problem with the MAP sensor wiring or software calibration (when the EMS 
detects  that  the  MAP  Volts  are  above  or  below  the  min/max  limits  it  will  run  in  a 
failsafe mode using the TPS-to-Load table to generate an artificial Engine Load signal 
using the Throttle input). This may allow the engine to sputter or start but not continue 
running properly.  
 
 
 
Sufficient battery voltage during cranking (starting) 
Having  enough  battery voltage  when  you  crank  over  your  vehicle  is  critical  to  the 
operation  of  your  vehicle  and  your  AEM  EMS.  For  the  EMS  to  function  properly,  the 
battery voltage must remain at or above 8 Volts when the vehicle is first starting. This 
is the time when your electrical system will be worked its hardest and be at its lowest 
voltage.  If  you  are  connected  to  your  Series  2  EMS  with  a  USB  communications 
cable,  and  you  experience  disconnecting  while  the  vehicle  is  cranking,  the  reason 
may  be  a battery  voltage  of  less than  8  volts.  If  this is the  case,  you  can  confirm  this 
by connecting with a serial cable (a serial adapter may be required if your computer is 
not  equipped  with  a  serial  port)  and  check  in  the  AEMTuner  software  for  a  Channel 
called  “Run  Time”.  “Run  Time” is  the  amount  of  time,  in  seconds,  that  the  EMS  has 
been  turned  on  for.  If  you  notice  that  this  Channel  goes  to  zero  while  the  EMS  is 
communicating  with  the  computer  and  the  vehicle  is  being  cranked,  that  means  the 
EMS has had lower than 8 Volts at some point and has reset the system. A thorough 
wiring  check  may  reveal  a  large  voltage  drop  causing  this  problem,  or  it  may  simply 
be the need for a new or a larger battery.  
						

							Page 16 of 21 
Application Notes for EMS P/N 30-6820 / 30-6821 
Subaru Impreza WRX STI (USDM 2.5L) 
Make: Subaru   Description Function ECU Pin # 
Model: Impreza WRX STI  Spare Injector Driver (max 1.5A): Injector 5 C2 
Years Covered: 2004 (30-6820 EMS) 2005-2006 (30-6821 EMS)  Spare Injector Driver (max 1.5A): Injector 6 C1 
Engine Displacement: 2.5L  Spare Injector Driver (max 1.5A): Injector 7 A6 
Engine Configuration: Flat 4  Spare Injector Driver (max 1.5A): Injector 8 A7 
Firing Order: 1-3-2-4  Spare Coil Driver (0-5V falling edge): Coil 5 B13 
N/A, S/C or T/C: Turbocharged  Spare Coil Driver (0-5V falling edge): Coil 6 B14 
MAP Min: 0.8V @ -14.7 PSIg  Boost Solenoid: PW 2 A32 
MAP Max: 4.59V @ 23.8 PSIg  EGT 1 Location: EGT 1 C12 
# Coils: 4, with internal igniters  EGT 2 Location: EGT 2 D20 
Ignition driver type: 0-5V, Falling Edge trigger  EGT 3 Location: EGT 3 D24 
# of Injectors: 4 (Inj 1-4)  EGT 4 Location: EGT 4 D29 
Factory Injectors: 500 cc/min saturated  Spare 0-5V Input Channel: ADCR 13 A33 
Factory Inj Resistors: No  Spare 0-5V Input Channel: ADCR 11 C27 
Injection Mode: Sequential  Spare 0-5V Input Channel: ADCR 14 C26 
Knock Sensors used: 1 (Knock 1)  Spare Low Side Output Driver: Low side 2 A13 
Lambda Sensors used: 2 (aftermarket wideband sensor required, OEM O2 sensors not supported) 
 Spare Low Side Output Driver: Low side 3 A12 
   Spare Low Side Output Driver: Low side 4 A14 
   Spare Low Side Output Driver: Low side 11 A24 
Idle Motor Type: None (Electronic Throttle)  Spare Low Side Output Driver:   
Main Relay Control: Yes (Switch 1 in, Coil7 output)  Spare Low Side Output Driver:   
Crank Pickup Type: Magnetic  Spare Low Side Output Driver:   
Crank Teeth/Cycle: 36-2-2-2  Spare Low Side Output Driver:   
Cam Pickup Type: Hall Effect  Spare Low Side Output Driver:   
Cam Teeth/Cycle: 3  Spare Low Side Output Driver:   
Transmissions Offered: Manual  Spare Low Side Output Driver:   
Trans Supported: Manual  Check Engine Light: Low side 10 A17 
Drive Options: AWD  Spare High Side Driver: High side 1 B34 
Supplied Connectors: ---  Spare High Side Driver:   
AEM Extension/patch harness 30-2988   Spare High Side Driver:   
AEM Plug/pin kit: N/A  Spare High Side Driver:   
     Spare High Side Driver:   
     Spare High Side Driver:   
     VVC Low Side Driver (RH cam): Injector 9 A28 
     VVC Low Side Driver (LH cam): Injector 10 A29 
     Spare Switch Input  (switch to GND): Switch 2* C9 
     Spare Switch Input: (switch to +12V) Switch 3** A1 
     Spare Switch Input (switch to GND): Switch 4* D11 
     Spare Switch Input (switch to GND): Switch 5* D13 
     Spare Switch Input (switch to +12V): Switch 6** D16 / D17  
Wire View of AEM EMS 
 
WARNING:      
*Switch  input  pins Switch  2,  Switch4,  Switch5 must  connect  to  ground;  the  switch  should  not 
provide 12V power to the EMS because that will not be detected as on or off. 
 
**Switch input pins Switch 3, Switch6, must connect to +12V; the switch should not provide GND to 
the EMS because that will not be detected as on or off.  22
10789111210101213141511981615141312111089212019181716151413121110
Connector A
2723222426251619
Connector B
312928301718222021242320
Connector C
181719212215
Connector D
14131716
12354619781243567234567123456
2119181716151413122011
Connector E
252423262731282930
741235689  
						

							Page 17 of 21 
Connection Diagram for EMS P/N 30-6820 
PnP The Plug and Play system comes with this configured for proper operation of this device. It is available for reassignment. 
Available The function is not currently allocated and is available for use 
Dedicated The location is fixed and cannot be changed 
Not used The AEM EMS does not use this pin location for this application  
Pin  2004 STI 2.5L / 2005-2006 STI 2.5L AEM EMS 30-6820  EMS I/O EMS pin description 
A1 Clutch Switch Switch 3 In Available, switch should connect to +12V when closed 
A2 Front Oxygen Sensor Heater (Signal 2) Injector 5 Out Available, can be used for additional injectors (1.5A max) 
A3 Front Oxygen Sensor Heater (Signal 1) Injector 6 Out Available, can be used for additional injectors (1.5A max) 
A4 --- Sensor Ground Out  Dedicated, sensors only, connects to pin C31 
A5 --- O2 #1 In Available, 0-5V  O2 sensor #1, connects to pin A26 
A6 GND (Front Oxygen A/F Heater 2) Injector 7 Out Available, can be used for additional injectors (1.5A max) 
A7 GND (Front Oxygen A/F Heater 1) Injector 8 Out Available, can be used for additional injectors (1.5A max) 
A8 Tumble Generator Valve RH (close) Idle 6 Out PnP for TGV 
A9 Tumble Generator Valve RH (open) Idle 5 Out PnP for TGV 
A10 Tumble Generator Valve LH (close) Idle 8 Out PnP for TGV 
A11 Tumble Generator Valve LH (open) Idle 7 Out PnP for TGV 
A12 Pressure control solenoid valve (fuel tank) Low Side  3 Out Available, can be used for Switched Ground (1.5A max)  
A13 Drain Valve  Low Side  2 Out Available, can be used for Switched Ground (1.5A max)  
A14 Purge Control solenoid valve Low Side  4 Out Available, can be used for Switched Ground (1.5A max)  
A15 Main light   (Cruise lamp on dash) Cruise light Out Dedicated, ETC system output 
A16 Cruise Set light (Set lamp on dash) Set light Out Dedicated, ETC system output 
A17 Malfunction Indicator Lamp Low Side 10 Out Available, can be used for Switched Ground (1.5A max) 
A18 Oil flow control solenoid (RH) Signal (+) +12V Switched Ignition Power Out Dedicated, also connects to A19, B5, B6 
A19 Oil flow control solenoid (LH) Signal (+) +12V Switched Ignition Power Out Dedicated, also connects to A18, B5, B6 
A20 --- ---   Not Used 
A21 --- ---   Not Used 
A22 Alternator Low Side 1 Out Available, can be used for Switched Ground (1.5A max) 
A23 Engine Speed Output (to OEM tachometer) Tacho out (LS7) Out PnP for Tachometer 
A24 Fuel Tank sensor control valve Low Side 11 Out Available, can be used for Switched Ground (1.5A max) 
A25 Front Oxygen sensor shield ---   Not Used 
A26 Front Oxygen sensor signal (-) O2 #1 In Available, 0-5V  O2 sensor #1, connects to pin A5 
A27 --- ---   Not Used 
A28 Oil flow control solenoid (RH) Signal (-) Injector 9 Out PnP for VVC #1   (Active Valve Control Solenoid) 
A29 Oil flow control solenoid (LH) Signal (-) Injector 10 Out PnP for VVC #2   (Active Valve Control Solenoid) 
A30 --- ---   Not Used 
A31 --- ---   Not Used 
A32 Wastegate Control solenoid valve PW 2 Out PnP for Boost Control Solenoid 
A33 Front Oxygen sensor signal (+) ADCR13 Out Available, 0-5V sensor 
A34 Engine Ground Power Ground In Dedicated, also B1,B4,B12,B31,C32,C33,D1,D2,D7,D31  
 1234567
8910111213141516
181920212223
Connector DConnector CConnector BConnector A
Wire View Of AEM EMS
2932303128
17
24252627
3334
1716151413121110
31
23
3534
2627
32
212220
30
7653421
89
2829
1819
2425
33
8910111213141516
18
28
2722
3234
25262423
303129
202119
654321
7
17
3533
891011121314151617
18
2631
22
2830
252423
27
202119
7654321
29  
						

							Page 18 of 21 
  
Pin  2004 STI 2.5L / 2005-2006 STI 2.5L AEM EMS 30-6820  EMS I/O EMS pin description 
B1 GND (Power Supply) Power Ground In Dedicated, also A34,B4,B12,B31,C32,C33,D1,D2,D7,D31 
B2 Rear Oxygen Sensor heater signal ---   Not Used 
B3 --- ---   Not Used 
B4 GND (Power Supply) Power Ground In Dedicated, also A34,B1,B12,B31,C32,C33,D1,D2,D7,D31 
B5 Control Unit Power Supply +12V Switched Ignition Power In Dedicated, also connects to A18, A19, B6 
B6 Control Unit Power Supply +12V Switched Ignition Power In Dedicated, also connects to A18, A19, B5 
B7 --- ---   Not Used 
B8 Camshaft position sensor (LH) Vehicle Speed In PnP for Cam sensor (LH) 
B9 Camshaft position sensor (RH) Cam In PnP for Cam sensor (RH) 
B10 Crankshaft position sensor Signal (+) Crank In Dedicated 
B11 --- ---   Not Used 
B12 GND (Ignition System) Power Ground In Dedicated, also A34,B1, B4,B31,C32,C33,D1,D2,D7,D31 
B13 --- Coil 6 Out Available Coil 6 output,  0/5V falling edge trigger 
B14 --- Coil 5  Out  Available Coil 5 output,  0/5V falling edge trigger 
B15 Ignition Control #4 Coil 4 Out PnP for Coil 4,  0/5V  falling edge trigger    
B16 Ignition Control #3 Coil 3 Out PnP for Coil 3,  0/5V  falling edge trigger    
B17 Ignition Control #2 Coil 2 Out PnP for Coil 2,  0/5V  falling edge trigger    
B18 Ignition Control #1 Coil 1 Out PnP for Coil 1,  0/5V  falling edge trigger    
B19 Back-up Power Supply Permanent +12V In Dedicated, back-up power for internal datalog memory 
B20 --- ---   Not Used 
B21 --- ---   Not Used 
B22 Crankshaft position sensor Signal (-) Timing Ground Out Dedicated, timing sensors only 
B23 --- ---   Not Used 
B24 Radiator Fan relay 2 control Low Side 9 Out PnP for A/C Fan 
B25 Radiator Fan relay 1 control Low Side 8 Out PnP for Radiator Fan 
B26* Fuel Pump control unit Signal 1 / Vehicle Speed* FPCU circuit (Coil 8) / Spare Speed* Out* Dedicated, 0-5V signal to Fuel Pump Control Unit 
B27* Vehicle Speed / Fuel Pump control unit sig 1* Spare Speed / FPCU circuit (Coil 8)* In* PnP for wheel speed input, shared with speedometer 
B28 --- CANH   Dedicated 
B29 --- CANL   Dedicated 
B30 --- ---   Not Used 
B31 Crankshaft Position sensor Shield Power Ground Out Dedicated, also A34,B1, B4,B12,C32,C33,D1,D2,D7,D31 
B32 --- ---   Not Used 
B33 A/C relay control Low Side 6 Out PnP for A/C compressor clutch 
B34 --- High Side 1 Out Available switched +12V output driver 
B35 Electronic Throttle control motor relay ETC relay control Out Dedicated  
 1234567
8910111213141516
181920212223
Connector DConnector CConnector BConnector A
Wire View Of AEM EMS
2932303128
17
24252627
3334
1716151413121110
31
23
3534
2627
32
212220
30
7653421
89
2829
1819
2425
33
8910111213141516
18
28
2722
3234
25262423
303129
202119
654321
7
17
3533
891011121314151617
18
2631
22
2830
252423
27
202119
7654321
29  
						

							Page 19 of 21 
 
  
Pin  2004 STI 2.5L / 2005-2006 STI 2.5L AEM EMS 30-6820  EMS I/O EMS pin description 
C1 --- Injector 6  Out Available, can be used for additional injectors (1.5A max) 
C2 --- Injector 5 Out Available, can be used for additional injectors (1.5A max) 
C3 Fuel Injector #4 Injector 4 Out PnP for Injector 4  (Peak & Hold  4A / 1A  driver) 
C4 Fuel Injector #3 Injector 3 Out PnP for Injector 3  (Peak & Hold  4A / 1A  driver) 
C5 Fuel Injector #2 Injector 2 Out PnP for Injector 2  (Peak & Hold  4A / 1A  driver) 
C6 Fuel Injector #1 Injector 1 Out PnP for Injector 1  (Peak & Hold  4A / 1A  driver) 
C7 Main switch Main Switch In Dedicated, ETC system input 
C8 Brake Switch 2 ---   Not Used 
C9 Brake Switch 1 Switch #2 In Available, switch should connect to GND when closed 
C10 Resume / Accel switch ---   Not Used 
C11 Set / Coast switch Set Switch In Dedicated, ETC system input 
C12 Fuel Temperature Sensor signal EGT #1 In Available, jumper set for 0-5V input 
C13 Intake Air Temperature sensor signal AIT In PnP for Air Intake Temp sensor, RTD type thermistor 
C14 Engine Coolant Temperature sensor Coolant In PnP for Coolant Temp sensor, RTD type thermistor 
C15 Accelerator Pedal Position sensor Power Accelerator Pedal +5V reference Out Dedicated, reference power to accelerator pedal 
C16 Electronic Throttle control Power Supply +5V Sensor reference Out Dedicated, sensor reference power 
C17 Accelerator Pedal Position sensor Main Accelerator Pedal signal 1 In Dedicated, main 0-5V signal from accelerator pedal 
C18 Electronic Throttle control Main TPS / Electronic Throttle signal 1 In Dedicated, main 0-5V signal from throttle motor 
C19 --- ---   Not Used 
C20 Fuel Level Sensor ---   Not Used 
C21 Fuel Tank Pressure Sensor signal ---   Not Used 
C22 Manifold Absolute Pressure sensor signal MAP In PnP for Manifold Pressure sensor 
C23 Mass Air Flow sensor Signal MAF In Available, 0-5V MAF input signal 
C24 -- Knock 2  In Dedicated, software – configurable knock filter circuit 
C25 Knock Sensor Signal Knock 1 In Dedicated, software – configurable knock filter circuit 
C26 Tumble Generator Valve position sensor LH  ADCR14 In PnP for TGV,  0-5V  input 
C27 Tumble Generator Valve position sensor RH ADCR11 In PnP for TGV,  0-5V input 
C28 Accelerator Pedal Position sensor Sub Accelerator Pedal signal 2 In Dedicated, secondary 0-5V signal from accelerator pedal 
C29 Electronic Throttle control Sub Electronic Throttle signal 2 Out Dedicated, secondary 0-5V signal from throttle motor 
C30 --- ---   Not Used 
C31 Mass Air Flow sensor GND Sensor Ground Out Dedicated, sensors only, connects to pin A4, C35,  
C32 Mass Air Flow sensor Shield Power Ground Out Dedicated, also A34,B1, B4,B12,B31, C33,D1,D2,D7,D31 
C33 Knock Sensor Shield Power Ground Out Dedicated, also A34,B1, B4,B12,B31,C32,D1,D2,D7,D31 
C34 Accelerator Pedal Position sensor GND Accelerator Pedal Ground Out Dedicated, ground to accelerator pedal 
C35 GND (sensor) Sensor Ground Out Dedicated, sensors only, connects to pin A4, C31,  
 1234567
8910111213141516
181920212223
Connector DConnector CConnector BConnector A
Wire View Of AEM EMS
2932303128
17
24252627
3334
1716151413121110
31
23
3534
2627
32
212220
30
7653421
89
2829
1819
2425
33
8910111213141516
18
28
2722
3234
25262423
303129
202119
654321
7
17
3533
891011121314151617
18
2631
22
2830
252423
27
202119
7654321
29  
						

							Page 20 of 21 
 
  
Pin  2004 STI 2.5L / 2005-2006 STI 2.5L AEM EMS 30-6820  EMS I/O EMS pin description 
D1 GND (control systems) Power Ground In Dedicated, also A34,B1, B4,B12,B31,C32,C33,D2,D7,D31 
D2 GND (control systems) Power Ground In Dedicated, also A34,B1, B4,B12,B31,C32,C33,D1, D7,D31 
D3 Electronic Throttle control GND (sensor) Electronic Throttle Ground Out Dedicated 
D4 Electronic Throttle control motor (-) Electronic Throttle Motor -  Out Dedicated, ETC system output 
D5 Electronic Throttle control motor (+) Electronic Throttle Motor +  Out Dedicated, ETC system output 
D6 Electronic Throttle control Motor Power Electronic Throttle Power In Dedicated, ETC power 
D7 GND (Injectors) Power Ground In Dedicated, also A34,B1, B4,B12,B31,C32,C33,D1,D2,D31 
D8 Starter switch Main Relay circuit (Switch #1) In Dedicated 
D9 Neutral Position switch ---   Not Used 
D10 Power Steering oil pressure switch ---   Not Used 
D11 Rear Defogger switch Switch #4 In Available, switch should connect to GND when closed 
D12 (not used by stock ECU) ---   Not Used 
D13 Blower Fan switch Switch #5 In Available, switch should connect to GND when closed 
D14* Test Mode Connector / Ignition Switch* --- / Main Relay circuit (Switch1)* * Not Used 
D15* Ignition Switch / Test Mode Connector* Main Relay circuit (Switch 1) / --- * In* Dedicated 
D16* AC Switch / Main Relay control* Switch 6 / Main Relay circuit (Coil 7) * In* PnP for A/C request switch 
D17* Main Relay control / AC Switch* Main Relay circuit (Coil 7) / Switch 6 * Out* Dedicated, activates main relay with switched GND 
D18 --- ---   Not Used 
D19 --- ---   Not Used 
D20 SSM / GST communication line EGT #2 In Available, jumper set for 0-5V input 
D21 --- ---   Not Used 
D22 --- ---   Not Used 
D23 --- ---   Not Used 
D24 Blow-by Leak diagnosis signal EGT #3 In Available, jumper set for 0-5V input 
D25 Rear Oxygen sensor Signal Lambda #2 In Available, 0-5V O2 #2 signal 
D26 --- ---   Not Used 
D27 --- ---   Not Used 
D28 Fuel Pump control unit Signal 2 Low Side Driver #5 Out Available, can be used for Switched Ground (1.5A max)  
D29 -- EGT #4 In Available, jumper set for 0-5V input 
D30 --- ---   Not Used 
D31 Rear Oxygen sensor Shield Power Ground Out Dedicated, also A34,B1, B4,B12,B31,C32,C33,D1,D2,D7        
  
 
 
 1234567
8910111213141516
181920212223
Connector DConnector CConnector BConnector A
Wire View Of AEM EMS
2932303128
17
24252627
3334
1716151413121110
31
23
3534
2627
32
212220
30
7653421
89
2829
1819
2425
33
8910111213141516
18
28
2722
3234
25262423
303129
202119
654321
7
17
3533
891011121314151617
18
2631
22
2830
252423
27
202119
7654321
29