^OPM^

just been out for a blast in car and pulled off sharply from lights and on came my check engine light malfunction indicator-according to book it monitors emissions-the car is a MY01 wrx with only exhaust mod is centre cat is removed and a diff backbox so emissions should be ok-im hoping that putting foot down just jolted something so it will go out when i reset ECU but rather then drive x amount of miles risking it -i was once told by a subaru garage that you can reset them by turning ur ignition on and off so many times or something-can anyone enlighten me to correct method please

virgin

This is only applicable to MY93-00 (GCA) models. The later model MY01 (GDA) onwards require the use of a product such as the DeltaDash or similar to reset the ECU. Please see www.ecutek.com.au/delta-dash.htm for more information.
ECU clear memory procedure is as follows for auto and manual transmissions:
1. With engine at operating temperature, turn engine off. Place gear shift lever into park (auto transmission cars only)
2. Locate the two ECU check connectors, for most cars they are located under the steering column and consist of a black plastic male and female connector, and a green male female connector. The exact location of the connectors varies with the different year models, but generally they are located under the steering column on the drivers side.
NOTE: sometimes they are still taped over with some small amount of plastic tape, so look hard, they will be there!
With the ignition OFF connect black to black and green to green.
3. Turn on ignition, do not start the engine, (and for auto transmission, cycle the gearshift lever from park to neutral and back to park ), depress the accelerator pedal to full throttle and hold for a few seconds, and then release.
Start engine and then drive for at least one minute, keeping road speed above 11 Km/h.
4. ECU is now re-set.
5. At this point the check engine light should start to flash the all clear signal (steady 1/2 second interval flashes). If the check engine light does not flash, or indicates some other sequence, there is a fault present in the system, and should be professionally checked for necessary repairs.
6. Once, stop the car and turn off the engine.
7. Disconnect the plugs.
8. Job complete.

^OPM^

thanks for reply but there is deffo a way even for new age cars to reset the ECU urself with no bits of kit needed

virgin

disconnect the battery for two hours so all power drains from the capacitors in the ecu,this will reset it

^OPM^

not so easy as i have a sigma alarm and soon as i disconnect battery off the alarm goes -dont think my neighbours would be too keen on that for 2 hours lol

greasemonkey

No there isn't. The only way to reset these ECU's is with an external device like a Select Monitor/Delta Dash etc. You can disconnect the battery for as long as you want, the ECU has a non-volatile memory that retains info through a power removal.

virgin

yep, that would be right greasemonkey but only on Myo1 forwards............i think

greasemonkey

That's correct Virgin, but seeing as ^OPM^ has an MY01 WRX, mentioning the reset technique employed by the earlier ECU's is a bit moot.

^OPM^

all sorted now just started car to day and no light on-thanks for replies

greasemonkey

Let's put that incorrect rumour to bed then. The ECU's on the MY01 and onward cars are OBDII compliant, and the only way to reset an OBDII ECU is via an external scan tool, Select Monitor, DeltaDash or some other external device.

The real story behind the rumour is that if the CEL is triggered, but if the cause is one of the more minor errors which subsequently disappears, the CEL will switch off after five engine starts. However, the ECU does not reset, and the cause of the error will remain in the DTC memory.

Eh? Don't recall saying that it would.