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AEM Standalone EMS Series 2 ( Part Number:AEM 30-6821)

AEM Standalone EMS Series 2

Part #: AEM 30-6821
MSRP: This Item is no longer available.


Brand: AEM
Base Map Included: Yes
Cam Advance Control: Yes
Data logging: Yes
Fuel Control: Yes
Ignition Control: Yes
Knock Activity readout: Yes
Knock Correction: Yes
Laptop Tunable: Yes
MAF Scaling: Yes
Model Specific: Yes
Plug and Play: Yes
Pre-Programmed Maps: Start Up Map Only
Sensors: Uses OEM
Stage Maps Included: No
Wiring Required: No

Mfgr. Warranty: 1 Year
Condition: New Product
Return Policy:

RallySport Guarantee - 30 Days

Items that are covered under the RallySport Guarantee offer a 30 day no questions asked return policy.

RallySport Guarantee items may be returned within 30 days of the original invoice date and must include all the original parts and contents for a refund.

The RallySport Guarantee does not apply to products that have been modified, damaged, misused or abused. All returns require an RMA (Return Merchandise Authorization) Number, and freight charges are strictly non-refundable. For more information regarding our freight refund policy, please refer to our return policy page found HERE.


AEM's Series 2 EMS is a complete engine control system that plugs into the factory harness and uses the factory sensors. This means you do not need to replace any parts of the harness or sensors, just plug the EMS into the harness and begin tuning! The Series 2 EMS for the Subaru STI allows you to control every aspect of your EJ25 from cam control to rev limit, timing, bigger injectors, boost control, nitrous injection, and individual cylinder fuel and timing trims. For drag racers there's even anti-lag! Professional tuners will appreciate the ease of use and security features on AEMTuner, the interface software for all Series 2 EMS systems.

Plugs directly into the factory harness. No rewiring necessary.
Uses all the factory sensors.
Includes start up calibrations.
System is fully enabled and unlocked - Never pay for upgrades!
Context sensitive help eases tuning process.
Maps can be password protected by the tuner to prevent unauthorized usage or sharing.
Runs on Windows-compatible software.
Up to 12 peak and hold injector drivers.
Up to 8 direct-fire coil outputs.
Up to 16 general-purpose outputs.
Up to 8 definable switch inputs.
Up to 4 EGT inputs with fuel trim.
1MB of internal data logging.
Electronic boost control.
Full idle control.
Programmable traction control.
Software definable knock control.
Two step launch control.
User configurable soft-cut rev limiters.
Wet or dry nitrous control.
Tune using new USB communication port or serial port.
Works with all AEM gauges
This product has no user uploaded media. You can upload your photo or video of your install by posting a review. Reviews:

  • Q: 2005 sti  Imprezanetics 2 years ago


    hi i have a 2005 sti will the aem ems let me remove the factory maf sensor and install a map sensor, and let me delete the the tgv system?

    • A: You can change to a MAP sensor with the correct modifications and ECU calibrations. You can also delete the TGV system. The most important aspect of both of these modifications is the tune after installation.

      Josh P. 2 years ago
  • Q: plug and play?  Attia199 3 years ago


    I have received my ECU recently. Looking through the instructions it states to re pin switch 2,4 and 5 to a ground. Then switch 3 and 6 to a 12v source. Im confused how this is a plug and play as stated in the description no rewiring necessary . Do i re pin or dont I? 2006 STI

    • A: If you are using the factory clutch switch, brake switch, rear defogger switch, blower fan switch, and A/C switch, then you do not need to re-pin anything. If you delete any of the above switches, then you will need to make sure those pins are connected to either power or ground, depending on which switch it is.

      Zach G. 3 years ago
  • Q: 04 sti engine  alaskanwhitey 3 years ago


    I'm swapping my 05 wrx block for my rebuilt 04 sti block and I was wondering if this standalone would be appropriate for my soon to be setup and if not if there is one yout would recommend along with a part number for ease of research? Thank you for your assistance! RSD rocks my socks off!

    • A: The shortblock will not affect the compatibility or function of this standalone, but you will need a 2005-2006 STI wiring harness, heads and sensors. We currently do not carry a standalone for your application and you may want to consider a piggyback system for the stock ECU.

      Brady R. 3 years ago
  • Q: engine light  wishing4askyline 4 years ago


    Will it still turn on the check engine light on when something goes wrong ?

    • A: Since this is a function of the stock computer/OBD this function is not available in the AEM Series 2. However the light can be triggered for different things. For instance over boost, shift light, etc.

      Greg N. 4 years ago
    • A: This is a full stand alone ECU and unlike the stock ECU will not trigger CEL's for emission devices. You can also set your own parameters to when/how you want the CEL to go off.

      Kirill C. 4 years ago
  • Q: Standalone ECU  Marc99875 4 years ago


    would this work with a 1988 mustang gt 5.0?

    • A: This is a direct plug and play unit for a Subaru. AEM does make universal EMS systems that you can hard wire into any car and set it up to your needs.

      Kirill C. 4 years ago
    • A: Unfortunately this unit will not work on the mustang. However you can look into using a 30-6050 that will work on your vehicle however will require custom wiring ad calibration.

      Greg N. 4 years ago