Engine · Subaru

Subaru EJ and FA: what the engine asks of an ECU

Page data last updated 2 October 2026

Subaru variants split on AVCS: single, which is intake only, or dual, which is intake and exhaust. Each variable cam adds a cam position sensor and a solenoid, and the cam sensor type is not the same across variants.

That makes the cited rows below matter more than usual.

Where this comes from

Some items on this page are cited from Wikipedia and from ECU manufacturers such as Haltech, not from the engine's maker. Each row names its source, and a † marks a row that is crowdsourced. Always check your specific sensors and manuals where you have them.

A figure like 58x is pulses per crank revolution from one sensor. It is a rate, not a sensor count, and it does not say whether the sensor is VR or Hall. The planner reads sensor type, cam sensor count and variable cams from the cited text. Where the text does not settle one, the row says so: check your sensor.

Variants

EJ20 turbo single-AVCS (EJ207 v7-9)

Engine
4 cylinders, flat layout1
Aspiration
Turbo2
Fuel injection
Port injection, sequential †
Ignition
COP, smart coils (igniter built in)2
Crank trigger
36-2-2-2 VR2
Cam trigger
2x VR (intake AVCS feedback)2
Cams and variable timing
4 camshafts; variable timing: 2 (single-AVCS intake: 2 solenoids + 2 cam sensors)1, 2 †
Firing order
1-3-2-41
Factory ECU
Subaru1
Notes
Single AVCS (intake only, roughly 2000 to 07): two AVCS solenoids and two cam sensors. Smart COP coils (internal igniter, driven directly by the ECU). Excludes the rare early EJ20G, which is wasted-spark. †

† Crowdsourced. This figure comes from builder and parts-supplier pages, not from the engine's maker or an ECU manufacturer. Treat it as a lead, then check your specific sensors and manuals.

How the planner reads the trigger text

Crank sensor type
VR (reluctor)
Cam sensor type
VR (reluctor)
Cam position sensors
2
Variable cams
2

Wire-in ECUs that cover it: 22 as they come, 24 more with add-on modules. The count is the planner's, worked out from the pin tables.

Fits as it is 22
Fits with add-ons 24

Plan a build around the EJ20 turbo single-AVCS (EJ207 v7-9)

EJ20 turbo dual-AVCS (EJ207 GRB 2008+)

Engine
4 cylinders, flat layout1
Aspiration
Turbo2
Fuel injection
Port injection, sequential3
Ignition
COP, smart coils (igniter built in)2
Crank trigger
36-2-2-2 VR2
Cam trigger
4x VR (AVCS feedback)3
Cams and variable timing
4 camshafts; variable timing: 4 (dual-AVCS int+exh: 4 solenoids + 4 cam sensors)1, 3
Firing order
1-3-2-41
Factory ECU
Subaru1
Notes
Dual AVCS (intake and exhaust, GRB, 2008 on): four AVCS solenoids and four cam sensors. Smart COP coils (internal igniter, driven directly by the ECU).3

How the planner reads the trigger text

Crank sensor type
VR (reluctor)
Cam sensor type
VR (reluctor)
Cam position sensors
4
Variable cams
4

Wire-in ECUs that cover it: 19 as they come, 27 more with add-on modules. The count is the planner's, worked out from the pin tables.

Fits as it is 19
Fits with add-ons 27

Plan a build around the EJ20 turbo dual-AVCS (EJ207 GRB 2008+)

EJ25 turbo single-AVCS (EJ257 2004-07)

Engine
4 cylinders, flat layout1
Aspiration
Turbo1
Fuel injection
Port injection, sequential1
Ignition
COP, smart coils (igniter built in)4
Crank trigger
36-2-2-2 VR4
Cam trigger
2x Hall (intake AVCS feedback)4
Cams and variable timing
4 camshafts; variable timing: 2 (single-AVCS intake: 2 solenoids + 2 cam sensors)1 †
Firing order
1-3-2-44
Factory ECU
Subaru1
Notes
US STI 2.5 turbo with single AVCS (intake only, 2004 to 07): two AVCS solenoids and two three-wire cam sensors. Smart COP coils (internal igniter, driven directly by the ECU).4

† Crowdsourced. This figure comes from builder and parts-supplier pages, not from the engine's maker or an ECU manufacturer. Treat it as a lead, then check your specific sensors and manuals.

How the planner reads the trigger text

Crank sensor type
VR (reluctor)
Cam sensor type
Hall
Cam position sensors
2
Variable cams
2

Wire-in ECUs that cover it: 19 as they come, 27 more with add-on modules. The count is the planner's, worked out from the pin tables.

Fits as it is 19
Fits with add-ons 27

Plan a build around the EJ25 turbo single-AVCS (EJ257 2004-07)

EJ25 turbo dual-AVCS (EJ257 2008+)

Engine
4 cylinders, flat layout1
Aspiration
Turbo1
Fuel injection
Port injection, sequential1
Ignition
COP, smart coils (igniter built in)4
Crank trigger
36-2-2-2 VR4
Cam trigger
4x Hall (AVCS feedback)4
Cams and variable timing
4 camshafts; variable timing: 4 (dual-AVCS int+exh: 4 solenoids + 4 cam sensors)1, 4 †
Firing order
1-3-2-44
Factory ECU
Subaru1
Notes
US STI 2.5 turbo with dual AVCS (intake and exhaust, 2008 on): four AVCS solenoids and four three-wire cam sensors. Smart COP coils (internal igniter, driven directly by the ECU).4

† Crowdsourced. This figure comes from builder and parts-supplier pages, not from the engine's maker or an ECU manufacturer. Treat it as a lead, then check your specific sensors and manuals.

How the planner reads the trigger text

Crank sensor type
VR (reluctor)
Cam sensor type
Hall
Cam position sensors
4
Variable cams
4

Wire-in ECUs that cover it: 17 as they come, 28 more with add-on modules. The count is the planner's, worked out from the pin tables.

Fits as it is 17
Fits with add-ons 28

Plan a build around the EJ25 turbo dual-AVCS (EJ257 2008+)

FA20D (BRZ/86 NA)

Engine
4 cylinders, flat layout5
Aspiration
Naturally aspirated5
Fuel injection
Port and direct injection, sequential5
Ignition
COP, smart coils (igniter built in)5
Crank trigger
36-2-2-2 VR5
Cam trigger
AVCS cam sensors5
Cams and variable timing
4 camshafts; variable timing: 4 (dual AVCS (int+exh))5
Firing order
1-3-2-45
Factory ECU
Subaru5
Notes
Toyota D-4S combined port and direct injection. About 12.5:1 compression. Smart COP coils (internal igniter), consistent with modern Subaru and Toyota COP.5

How the planner reads the trigger text

Crank sensor type
VR (reluctor)
Cam position sensors
4 assumed, check your sensor
Variable cams
4

Wire-in ECUs that cover it: 19 as they come, 26 more with add-on modules. The count is the planner's, worked out from the pin tables.

Fits as it is 19
Fits with add-ons 26

Plan a build around the FA20D (BRZ/86 NA)

FA20DIT (WRX turbo 2015+)

Engine
4 cylinders, flat layout5
Aspiration
Turbo5
Fuel injection
Direct injection, sequential5
Ignition
COP, smart coils (igniter built in)5
Crank trigger
36-2-2-2 VR5
Cam trigger
AVCS cam sensors5
Cams and variable timing
4 camshafts; variable timing: 4 (dual AVCS (int+exh))5
Firing order
1-3-2-45
Factory ECU
Subaru5
Notes
Direct injection only, with no factory port injection. About 10.6:1 compression. Smart COP coils (internal igniter), consistent with modern Subaru and Toyota COP.5

How the planner reads the trigger text

Crank sensor type
VR (reluctor)
Cam position sensors
4 assumed, check your sensor
Variable cams
4

Wire-in ECUs that cover it: 1 as they come, 45 more with add-on modules. The count is the planner's, worked out from the pin tables.

Fits as it is 1
Fits with add-ons 45

Plan a build around the FA20DIT (WRX turbo 2015+)

Pairing the engine with a gearbox? BoxSelector has the ratios for the boxes that bolt up to it, and works out road speed and tyre size before the money goes: gearbox ratios.

Sources

  1. Wikipedia: Subaru EJ engine Wikipedia · infobox, EJ207, Other Data, lead, EJ207 (DOHC flat-4: 2 camshafts per bank), EJ257 (STI)
  2. Haltech: EJ20 engine Haltech (ECU maker) · Model Variants, Ignition Coils and Igniter, Crank Sensor, Cam Sensor, Variable Cams
  3. Wikipedia: Active valve control system Wikipedia · Dual AVCS (one cam sensor per variable cam, 4); reluctor type per the Haltech EJ20 Cam Sensors section, Dual AVCS (late model EJ207 in the WRX STI); 4 = intake and exhaust on both banks, Dual AVCS (late model EJ207 in the WRX STI), Dual AVCS
  4. Haltech: EJ25 engine Haltech (ECU maker) · Ignition Coils, Crank Sensor, Cam Sensor, General Information, Cam sensors, Model Variants
  5. Wikipedia: Subaru FA engine Wikipedia · lead, Development, FA20D, infobox, FA20F

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