ECU spec · AEM

AEM Infinity Series 3 pinout and specs

Checked against the maker's documents 27 September 2026

AEM Infinity Series 3 is a 73-pin wire-in AEM ECU on 1 connector: C1 (73 pins).

It has 10 injector outputs and 9 ignition outputs. The injector drivers are peak-and-hold, so low-impedance injectors run without a resistor pack. Most ignition outputs are logic-level, with one direct coil driver for a distributor.

There are 4 dedicated trigger inputs; the maker does not say which sensor type. Two knock inputs cover both banks of a V engine. Wideband control needs an external controller, usually over CAN.

It does not drive an electronic throttle, so plan on a cable throttle. One CAN bus handles dashes, PDMs and expansion.

Spec sheet

ConnectorsC1 (73)73 pins in this profile
Injector outputs10peak-and-hold (low-impedance capable)
Ignition outputs9mixed: logic-level plus a direct coil driver
Dedicated trigger inputs4sensor type not stated
Knock inputs2
Onboard wideband controllers0
Onboard MAP sensorNot listed by the maker
CAN buses1
Drive-by-wireNo
High-side outputs0
Half-bridge outputs4H-bridge pairs for a throttle motor or stepper
5V sensor supply2 pins

Worth knowing

  • Infinity-308: 8 coil triggers plus 1 high-output driver for a distributor coil.
  • 8 high-impedance injector channels; injectors 1 and 2 also have peak-and-hold terminals for low-impedance use.

Which builds it suits

Of the 58 swap presets in the planner, 0 fit as they are and 27 fit with add-ons; 31 do not fit at all. The add-on it asks for most often is the AEM X-Series Inline Wideband UEGO (30-0310). Where it falls short, it is usually not enough drive-by-wire throttle motor (h-bridge). The planner fills anything a preset leaves open with its ordinary defaults, so your own build may land differently.

The Toyota 2JZ-GE VVT-i (coil pack) needs AEM X-Series Inline Wideband UEGO (30-0310) and an external igniter. The Nissan RB26DETT (R34, smart coils) needs AEM X-Series Inline Wideband UEGO (30-0310). It can't run the Toyota 2JZ-GTE VVTi: not enough drive-by-wire throttle motor (h-bridge). It can't run the Ford Coyote 5.0 Gen3 (2018-23): not enough drive-by-wire throttle motor (h-bridge). It can't run the Honda K24 (i-VTEC 2.4 NA): not enough drive-by-wire throttle motor (h-bridge).

Fits with add-ons 27
Does not fit 31

Plan a build around the AEM Infinity Series 3

Pin table

Connector C1 carries 10 injector outputs, 9 ignition outputs and 4 trigger inputs.

Show all 73 pins
PinFunction
C1 C1-1Coil 5
C1 C1-2Coil 3
C1 C1-3Stepper 1A (bipolar ±1.4A)
C1 C1-4Stepper 2A (bipolar ±1.4A)
C1 C1-5Stepper 2B
C1 C1-6Stepper 1B
C1 C1-7EFI Main Relay Switched Ground Output (0.7A sink)
C1 C1-8Crankshaft Position Sensor VR+
C1 C1-9Crankshaft Position Sensor VR-
C1 C1-10Camshaft Position Sensor 1 VR-
C1 C1-11Camshaft Position Sensor 1 VR+
C1 C1-12CANH A
C1 C1-13CANL A
C1 C1-14Coil 1
C1 C1-15Coil 4
C1 C1-16Coil 6
C1 C1-17Coil 7
C1 C1-18Ignition Switch (10K pulldown)
C1 C1-19Main Relay Power Input (12V)
C1 C1-20Knock Sensor 2
C1 C1-21Knock Sensor 1
C1 C1-22Analog Sensor Ground
C1 C1-23Analog Sensor Ground
C1 C1-24Crankshaft Position Sensor Hall (10K pull-up 12V)
C1 C1-25Camshaft Position Sensor 1 Hall
C1 C1-26Digital 2
C1 C1-27Dig3 [Hz]/Duty
C1 C1-28Dig4 [Hz]/Duty
C1 C1-29Digital 5
C1 C1-30Dig6 [Hz]/Duty
C1 C1-31Digital 7
C1 C1-32Coil 8
C1 C1-33Coil 2
C1 C1-34Battery Perm Power
C1 C1-35Main Relay Power Input (12V)
C1 C1-36Flash Enable (10K pulldown)
C1 C1-37Analog Temp 1 (default coolant)
C1 C1-38Analog Temp 2 (default air)
C1 C1-39Analog Temp 3 (default oil)
C1 C1-40Analog 7 (default primary TPS)
C1 C1-41Analog 8 (default MAP)
C1 C1-42Analog 9 (default fuel pressure)
C1 C1-43Analog 10
C1 C1-44+5V Sensor Power (regulated, fused)
C1 C1-45+5V Sensor Power (regulated, fused)
C1 C1-46Analog 11
C1 C1-47Analog 13 (default oil pressure)
C1 C1-48Analog 16
C1 C1-49Analog 18
C1 C1-50Analog 19
C1 C1-51Battery Ground
C1 C1-52Coil 1 HO (IGBT ignition driver, direct)
C1 C1-53Lowside 9 (2A)
C1 C1-54Lowside 8 (2A)
C1 C1-55Lowside 7 (2A)
C1 C1-56Lowside 6 (2A)
C1 C1-57Lowside 5 (2A)
C1 C1-58Injector 8 (hi-Z, 1.7A)
C1 C1-59Injector 6 (hi-Z)
C1 C1-60Injector 4 (hi-Z)
C1 C1-61Injector 2 (hi-Z)
C1 C1-62Injector 2 Peak&Hold (308) / not used (358)
C1 C1-63Injector 1 Peak&Hold (308) / not used (358)
C1 C1-64Injector 1 (hi-Z)
C1 C1-65Injector 3 (hi-Z)
C1 C1-66Injector 5 (hi-Z)
C1 C1-67Injector 7 (hi-Z)
C1 C1-68Lowside 4 (2A, 12V pull-up)
C1 C1-69Lowside 3 (2A)
C1 C1-70Lowside 2 (1.7A)
C1 C1-71Lowside 1 (2A)
C1 C1-72Lowside 0 (2A)
C1 C1-73Battery Ground

Other AEM ECUs

The closest AEM unit is the AEM Infinity Series 5. Against it, this one has 10 injector outputs (the Infinity Series 5 has 8), 9 ignition outputs (the Infinity Series 5 has 8), 0 wideband controllers (the Infinity Series 5 has 1) and 1 CAN bus (the Infinity Series 5 has 2).

Source: AEM document techlibrary_hardware-specification_infinity_series-3

Always verify against the manufacturer's manual and your tuner before wiring.

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