Resetting the ECU

[Guest]

I installed an aftermarket intake on my Legacy. I was wondering if I need to reset the ECU and if so, how do I do this?

Thanks

Will

[Guest]

 BigWillieStyles said:

I installed an aftermarket intake on my Legacy. I was wondering if I need to reset the ECU and if so, how do I do this?

Thanks

Will

ECU Reset

* With ignition OFF, locate the 2 black ECU check connectors and the 2 green ECU reset connectors below dashboard on left side of drivers foot well. There will be one female and one male of each color (Black & Green).

* Connect the black connectors together, and connect the green connectors together.

* Start the vehicle and drive until the check engine light starts flashing. ENSURE THE VEHICLE SPEED REMAINS ABOVE 11 Km/h.

* If there is no fault, the check engine light should flash steadily. If there is a fault, the check engine light will flash the appropriate code which can be checked against the table below and the fault rectified ASAP.

* Stop engine and turn ignition OFF.

* Disconnect the two black and two green connectors.

[Guest]

Thats awesome, thanks mate.

I was also just thinking, could I just unplug the battery? Doesnt this reset the ECU?

[Durty-Sanchez]

Sure does - leave it off for 24hrs, and this will only work with pre-2000 cars fo'sho. After 2000 it may save it's junk in non-volatile memory

[subieboy]

From Subaru's own Tech manual:

[5] How to carry out self-diagnosis

Method using Check Engine Lamp

<Read memory>

(1) Connect the read memory connector (black, 1 pole)

with ignition switch OFF.

(2) Ignition switch turned ON (engine stopped)

(3) Check if the check engine lamp blinks.

(4) Inspection

_ The lamp does not turn on.

.......Check an abnormality of the check lamp.

_ The lamp blinks (without display of DIAG code)

.......No display of DIAG code in the past → Perform

D check and confirm the current failure.

_ The lamp blinks (with display of DIAG code)

.......Display of DIAG code experienced in the past →

Perform checking based upon the DIAG code.

<D check>

(1) Engine warming up

(2) Ignition switch turned OFF

(3) Connection of test mode connector (green 2 poles)

(4) Ignition switch ON (Engine stops)

(5) Check engine lamp turning ON

Confirm that the check engine lamp turns ON.

(6) Inspection of the fuel pump

Confirm that functioning noise of the fuel pump can

be heard for 2 seconds after IG SW ON. You can perform

this check up from the pulses by touching the

fuel hose in the engine room.

If it is NG, check the fuel pump circuit.

(7) Inspection of solenoid valve

Confirm that functioning noise of canister purge solenoid

(clicking noise) can be heard. If it is NG, check

the solenoid valve circuit line.

(8) Inspection of radiator fan. Confirm that the radiator fan

functions intermittently. If it is NG, check the radiator

fan line circuit.

(9) Signal input to throttle sensor

Fully depress the accelerator pedal slowly, and then

release it.

(10)Starting the engine

Caution

In the case of vehicles with AT, be sure to start the

engine in P range.

If the engine does not start, check the engine for the disable

starting.

(11)Vehicle speed sensor signal input

Run your vehicle at the speed of 10 km/h.

(12)O2 sensor signal input

Activate O2 sensor by keeping the engine revolution

between 2,000 ~ 3,000 rpm for more than 1 minute.

(13)Check lighting of Check Engine Lamp.

(Normal) ........ Blinking

(Abnormal) .... Display of DIAG code

In the event that several DIAG codes are displayed,

diagnose the failure one by one starting with smaller

number.

After one repair (check) has been finished,

perform D check to see if the DIAG code has disappeared.

If other codes are displayed, proceed to the

said failure diagnosis

[Guest]

Thanks guys that stuff is great, I probably should of reset the ECU like that first. I actually reset the ECU by turning the battery off and then reconnecting it after one hour. Everything worked the same.

[Guest]

I was searching for this again, this thread should be stickied!

[G-unit]

yea i reset mine after replacing afm and other parts by leaving the battery off over night

[log1call]

All you have to do really is drive the car as you normally do. They are resetting and adapting to your car and your driving style the whole time. Resetting the ecu will often cause all the old settings that don't need adjusting, to be set to a less than optimum figure. Whatever you do, it wioll all be back to where it's needed after a couple of restarts and a ten minute drive if driven properly, ie, through all of it's speed and load ranges.