Is a seperate diagnostic tool required to get these?

How to check fault codes
Under the dash on the drivers side there are two black/white plugs and two green plugs... these are used to reset the computer as discussed in another thread.... to obtain fault codes from the computer you just have to connect the two black/white plugs together and then turn the ignition on. The CHECK ENGINE light will flash the code repeatedly. Long flashes are the first digit, short flashes are the second digit. ie. long-long-long-short would be code 31. There may be several codes and it will cycle through all of them then start the series again. If it justs flashes in half second bursts continually you have no codes.

How to reset the ECU
To erase trouble codes from the computer you have two ways. The first I have not verified, but I'm sure it works.
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).
· 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.
· 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 10 mph.
· ECU is now re-set.
· 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 checked for necessary repairs.
· Once done, stop the car and turn off the engine.
· Disconnect the plugs.

The way I usually erase the codes or "Reset the ECU" is by doing the infamous "battery dance."
NOTE: Do this on a "cold" engine. Leave it sit overnight and do it in the morning.
1. Disconnect the negative battery terminal cable for 45-60 minutes.
2. Reconnect the negative battery terminal cable.
3. Turn off all your accessories.
4. Start the car, but DO NOT touch the throttle at all.
5. Let the car idle for 10-15 minutes, or until the car is at normal operating temperature. Again, do not touch the throttle.
6. Turn the ignition key to the "OFF" position. That's it

FAULTS CODES:
11 Crank Angle Sensor or Circuit
12 Starter Switch or Circuit
13 Cam Position Sensor or Circuit (TDC Sensor on Justy)
14 Fuel Injector No. 1 (Legacy, Impreza, Justy, SVX)
15 Fuel Injector No. 2 (Legacy, Impreza, Justy, SVX)
16 Fuel Injector No. 3 (Legacy, Impreza, Justy, SVX)
17 Fuel Injector No. 4 (Legacy, Impreza, SVX)
18 Fuel Injector No. 5 (SVX)
19 Fuel Injector No. 6 (SVX)
21 Coolant Temperature Sensor or Circuit
22 Knock Sensor or Circuit (Right Side on SVX)
23 Air Flow Meter or Circuit (Exc. Justy)
24 Air Control Valve or Circuit (Exc. Justy)
25 Fuel injector No. 3 and 4 (XT-6)
26 Air Temperature Sensor (Justy)
28 Knock Sensor No. 2 (SVX, Left Side)
29 Crank Angle Sensor (SVX, No. 2)
31 Throttle Position Sensor or Circuit
32 Oxygen Sensor or Circuit (No. 1, Right Side, On SVX)
33 Vehicle Speed Sensor (VSS) or Circuit
34 EGR Solenoid or Circuit
35 Purge Control Solenoid or Circuit
36 Air Suction Solenoid Valve (Impreza)
37 Oxygen Sensor (No. 2, Left Side, On SVX)
38 Engine Torque Control (SVX)
41 Air/Fuel Adaptive Control
42 Idle Switch or Circuit
43 Throttle Switch
44 Wastegate Duty Solenoid (Turbo Models)
45 Pressure Sensor Duty Solenoid (Turbo Models)
45 Atmospheric Pressure Sensor or Circuit (Non-Turbo Models)
46 Neutral or Parking Switch or Circuit
47 Fuel Injector
49 Airflow Sensor
51 Neutral Switch (Manual Transmission Models)
51 Inhibitor Switch (Automatic Transmission Models)
52 Parking Brake Switch (Exc. Justy)
53 Fuel Pump or Circuit
54 Choke Control System
55 EGR Temperature Sensor or Circuit
56 EGR System
57 Canister Control System
58 Air Control System
61 Fuel Tank Pressure Control Solenoid (Impreza)
62 Fuel Temperature Sensor (Impreza)
63 Fuel Tank Pressure Sensor (Impreza)
64 Vacuum Line Control Valve or Circuit
65 Vacuum Pressure Sensor
66 Sequential turbo system
67 Exhaust valve solenoid (positive pressure)
68 Exhaust valve duty solenoid
71 Ignition Pulse System
73 Ignition Pulse System
74 Ignition Pulse System
88 TBI Control Unit

Disconnect the plugs and you're done.

yep thats them.

Just changed the o2 sensor and water temp sensor and it was still running badly. Did the reset with the plugs and it made a huge difference. The car now holds onto gears longer. It idles better and is just better all round. The best thing is its now reading the temp sensor correctly and not running rich all the time. Thanks for the sticky.:neo:

Ya know after posting those pics weeks ago I still haven't managed to reset my ECU!

Yep, two kids & a wife who works night shift - that'll do it.

Anyhoo... In the instructions on re-setting I notice that there's a point which says something along the lines of "get the car to running temperature". Is this for NA cars or turbos - or both?

...and if ithe car's a manual? Any gear or neutral?

Hate to be pedantic, but wanna make sure I get this right before I give it a go!

Then have to somehow sneak in making my home made CAI so the wife doesn't catch on - she thinks I'm wasting my time.

By the way - should I reset the ECU after installing CAI too? (Sorry - off topic a little)



Any help, as always, is appreciated guys!

regashi;141045 wrote:

I can understand nightshifts man. They're painful to say the least. Hats off to you for juggling all that with a wife and kids!

To answer your questions:

a) Always get car up to normal operating temperature. These cars have a system in place to compensate for the engine running at cooler temperatures (ie startup) by dumping more fuel in. To have the car running at optimum, you must have the car running at normal operating temperature. I suggest doing the reset after arriving home from work or something.

b) In a manual car, it has to be in neutral. Think about it. If the car is in gear, and you plug in the test connectors, and then start the car, what would you think would happen?! Once you have connected the test connectors, and carried out the correct procedure, you then have to take your car out for a drive...

c) Yes. Most definitely do an ECU reset after you install your CAI!

It can only help.  It may even throw up a code with a clue to your idle or it just may be the iacv.

No harm at all in doing it.

A steady flash interval @ 1/2 second means everythings good. If it flashes fast 2 times then slow 3 times for example thats code 23. You will be able to tell the difference in flash intervals.

If you get a code, the code readout is on here somewhere, Search for it or post up your code/s.

krusty;144880 wrote:

thanks heaps cruisn i got code 31-throttle position sensor, so we are in the process of getting it looked at or getting a new one,
thanks so much for the help

weezer;153079 wrote:

Funny thing is, both times it was around 11am the car wouldn't start, and both times it started after 12 lunchtime.

So, anyone have an idea what my cars problem is? Hope it's nothing serious. I just need to get to work for another week and it's all good, cos we're moving again, and I can walk to work then.

hey konvict, my genII had a simliar problem and after i did this it didnt and hasent since, now sure if it was dumb luck or whether this actually fixed it or not, maybe just try it

No Goran.

Reseting the ECU doesnt change any of the constants on the maps in the ecu.

So any data that was changed due to tuning will be unaffected.  Reseting the ECU will delete all the "learned" data that the ECU gets from you driving the car which will mean it will feel like it did the first time you drove it after you got it tuned.

Hey guys might be a dumb question but i have installed new exhaust from the cat back, and i am considering installing cold air intake system. Would resetting my ecu help or do i have to get it professionally tuned to make the most of the gains?