[Jakandra]

Thanks for your excellent advice @Bod. After a battery reconnection my Renault Kangoo lost the ability to rev up and supply enough power to drive faster than 10mph. I followed your advice to the letter and it fixed the problem. Thank you!

 

[alexanderNSW]

My recent experience verifies the relearn procedure, also.

*2006 Forester SG suddenly started idling <500rpm and stalling at lights
*I noticed that the bottom part of the air filter cover was not fitted correctly, so air could enter the intake duct bypassing the filter. (my fault when last servicing it)
*I removed the MAF/IAT sensor unit. the IAT was obviously dirty; it is hard to actually see up into the MAF but I cleaned them both with MAF cleaner spray.
*Also cleaned the throttle body around the butterfly, as it was obviously dirty. I believe the crud was impeding the small amount of air which gets past the butterfly at idle.
*That improve the situation but not completely, so I sprayed the sensor again, ran through the claimed relearn procedure and it was back to normal.

Exactly how long one needs to disconnect the battery, or how long to hold the key in the On position before starting, or how long to leave it idling, or whether repeating that is needed, are hard to say.
No doubt a Subaru tech would know. But the procedure certainly seems to work.

 

[08subfor]

Thanks for the info, @Bod.
I see enuf trolls in other fora I frequent.
Don't need 'm here, eh?

 

[1.618]

@08subfor Are the "idle reset deniers" back at it? It's a fact (for me anyway) that when the ECM is reset/dtc cleared the idle speed is also cleared. If you are fortunate enough to have a Subaru Select diagnostic tool, I believe you can simply instruct the ECM to set the idle speed. If like me you don't have access to such a tool, you have to create the proper conditions for the ECM to RELEARN the proper speed. Having done this many times, I now know what works and what doesn't for me and this particular car. What works is:
1. make sure all power accessories (lights, etc are OFF)
2. disconnect battery for 30 min
3. reconnect battery
4. note all following steps are done WITHOUT touching any pedal or switch... only the key
5. insert key and turn ON (without engaging starter) for 20 seconds
6. engage starter so engine starts, and set timer for twenty (20) minutes, let engine run for 20 minutes
7. turn key OFF and leave key in ignition for 20 seconds
8. remove key
9. repeat step 5 above
10. engage starter so engine starts, and set timer for ten (10) minutes, let engine run for 10 minutes
11. turn key OFF and leave key in ignition for 20 seconds
12. remove key, at which point ECM has repeated idle speed.

I ran across the procedure for doing this the "right" way with a Subaru scan tool, but I can't find it again right now.

I have been battling a problem with a DTC 0442 for a long time. Its a long story, but have replaced Drain Valve, Pressure Contr Valve, confirmed Purge Valve, good cap, was getting a bad I/O signal at ECM on both pins for PCV and Drain Valve and have replaced ECM, can't find a leak. The manuals don't say it in fiagnostic procedures, but am suspicious of pressure sensor, I guess I'll get back into it all... The car runs fine, I just can't get a safety sticker, which means I can't renew registration... Eventually am gonna get stopped for expired. Anyone have any experience with small evap leak beyond "replace cap" or "smoke test"?

 

[1.618]

In case anyone interested (this is probably not anything new for Subaru techs out there), here is the section I ran across in Service Manual... apparently after clearing memory, the Subaru Select Monitor can be used to reset the idle speed (point being that after clearing memory, the idle speed must be reset). I believe that UNLIKE my generic scan tool w/o the ability to select and actuate Subaru solenoids, a Subaru Select Monitor is a bi-directional scan tool with the ability to individually select and perform compulsory operation of all solenoids on a Subaru, and access the ROM on the ECM... this is a general statement, I'm not an expert.

Last statement on this, this Manual is for a 2007 Forester

 

[bbottomley]

I realize that there are situations where you do have to totally power down the car, but there are times where you just need to replace the battery or remove it from its permanent location in order to gain access to something nearby. In these situations, you can avoid the whole reset procedure by clipping a jump start box to ground and the positive battery connector before removing the connectors from the battery.

Just be extra careful that the exposed connections don't touch the wrong place.

 

[Harv707]

Hello
Just replaced my battery in my 2009 Outback 2.0 Navplus and although idling is not to bad there is a distinct hesitation in acceleration and distinct loss of power.
I am intending to do the idle relearn procedure but mine is push button start. Is the procedure the same for my car?
Any helpful advice is very much appreciated

 

[Theseus161]

 

[Harv707]

Many thanks Theseus161. Much better watching process as opposed to reading about it
Still unsure how I go about it on push button start but will give it a go

 

[QML]

Posting here as this seems to affect some Forester and Imprezza models with Electronic Throttle Bodies or IACV that undergo a battery disconnect, and lose their idle calibration.

As per these links to retrain the ECU idle parameters:

low and rough idle and stalling at complete stops. - NASIOC

low and rough idle and stalling at complete stops. Normally Aspirated Powertrain

forums.nasioc.com

New battery, now engine stalls - NASIOC

New battery, now engine stalls Service & Maintenance

forums.nasioc.com

Click Here for Instructions on: "HOW TO IDLE-RELEARN" - Car Forums and Automotive Chat

Click Here for Instructions on: "HOW TO IDLE-RELEARN" Lumina Car Forums

www.automotiveforums.com

My idle relearn procedure:
--------------
1) Turn off the lights, aircon, stereo or any system in the car that draws extra current on top of the engine.
2) Disconnect the battery for 30 mins.
3) Reconnect the battery.
4) Before you start the car for the first time, turn the key to the ON position but do NOT turn the engine over. Wait 10-15 seconds so the electronic throttle body or IACV has time to go to the factory programmed home position.
5) After waiting, start the car and let it idle without any load, lights, A/C etc.
6) Every 20 seconds or so the idle will be adjusted up and down as the ECU tries to adjust it towards a stoichiometric fuel / air mix.
7) Leave the engine running for a full 10 mins but DO NOT TOUCH THE ACCELERATOR during this time or turn on anything that will cause extra electrical current draw.
8) Turn off the engine, and leave the key in the OFF position for at least 20 sec.
9) As per step (4) turn the key back to the ON position for 10-15 sec without actually starting the engine.
10) Start the engine and leave to idle for a further 5 minutes without touching the accelerator and without turning on other systems in the car.
11) Turn off the engine again and wait at least 20 sec before restarting.
12) Take the car for a test drive as the ECU should now be fully retrained.
--------------
I know for a fact that this is necessary for the 2003 Forester XT because this process seems to have been the cause of all the teething problems with the LPG system because it was never retrained after the battery was disconnected during the conversion. I used an OBD2 adapter to measure the AFR beforehand - and the LPG AFR was waaay out in comparison to the petrol. After following the process above both sets of AFRs are now very close to a stoichiometric mix, and the car idles correctly without the revs bouncing up and down constantly.

This works great for my 2014 Subaru Forester 2.5i. I disconnected the battery for more than 30 mins to install a trailer hitch and instantly went to driving after reconnecting and the ECU probably got confused. Though, I stopped seeing the engine rpm bounce up and down after the 10-15 mins idling so Idk if that's good enough. I went through the whole procedure and I believe it's good now.
Also, I see some people said they didn't have to do this after disconnecting the battery. I think when you disconnect the battery for a short period of time (e.g. to change out the battery) it's sometimes not necessary to retrain the ECU. But that's just my observation...
Thank you so much for the helpful posting!

 

[08subfor]

@1.618 -- revisited after having to disconnect battery repeatedly at night to safeguard against a stolen second keyfob. Thanks!

 

[Bill Vang]

What a load of B.S. Internet mythology.
-- Steve

7 years late, but I second Bod on his suggestion. My power windows don't open automatically and my gas pedal response is not reactive as it's usual state. My car did also stall on the road when I noticed these things. I would have to blip the gas often just in case my car dies on the road.

 

[Kevin]

G'day & Welcome @Bill Vang So you are saying that it worked for you?

Could you please update your Public Profile; vehicle details at least; thanks. For detail instructions pls refer: Your forum "Public Profile" - how to fill this...

 

[knurledflanges]

Is it possible that situations where this procedure are needed indicate some other problem with the fuel system etc, and that's why the ECU switching to default settings results in stalling? It would seem like something drifting away from nominal functioning is a likely explanation for why so many can go through battery changes etc without having to do this, yet others with the same car get bitten by it.

 

[Bobbydiggs]

Sorry but I'm in the BS camp here too. Well, not BS but way overcomplicated. I've used the Vishnu method dozens of times.

Turn off everything. Disconnect the earth strap. Hit the brake pedal to use any residual current. Wait between 5 seconds and 2 days. Reconnect the battery. Drive without using boost to a road that is preferably long and straight and slightly uphill. Start to accelerate allowing boost to rise slowly and without getting too much. Continue for 30 seconds or thereabouts. The end. Your car will now idle and accelerate more smoothly and feel a little more powerful. If you haven't done this for a long time or even ever the effect will be more remarkable.

I realize this is very old and I’m only posting for anyone else who may stumble across this. But how is what you are recommending ANY different from what the op suggested with the exception of semantics? “Run out the electric, perform some kind of base idle learning etc” that’s crazy to say his is bs but
Yours is not?

 

[2.5x_sleeper]

@Bobbydiggs welcome to the forum from Oregon!

Please complete your "Public Profile - add your vehicle details!

Your forum "Public Profile" - how to fill this...

Welcome to the community! For the best forum experience, we recommend completing your "Account Details". The information you enter there will display when members click "About" in your forum profile. You can also create a custom "Signature" that will display every time you make a forum post...

www.subaruforester.org

Bobby...

['07 FSXT Member Journal] ['03 X Member Journal]

 

[Subfor16Jam]

Posting here as this seems to affect some Forester and Imprezza models with Electronic Throttle Bodies or IACV that undergo a battery disconnect, and lose their idle calibration.

As per these links to retrain the ECU idle parameters:

low and rough idle and stalling at complete stops. - NASIOC

low and rough idle and stalling at complete stops. Normally Aspirated Powertrain

forums.nasioc.com

New battery, now engine stalls - NASIOC

New battery, now engine stalls Service & Maintenance

forums.nasioc.com

Click Here for Instructions on: "HOW TO IDLE-RELEARN" - Car Forums and Automotive Chat

Click Here for Instructions on: "HOW TO IDLE-RELEARN" Lumina Car Forums

www.automotiveforums.com

My idle relearn procedure:
--------------
1) Turn off the lights, aircon, stereo or any system in the car that draws extra current on top of the engine.
2) Disconnect the battery for 30 mins.
3) Reconnect the battery.
4) Before you start the car for the first time, turn the key to the ON position but do NOT turn the engine over. Wait 10-15 seconds so the electronic throttle body or IACV has time to go to the factory programmed home position.
5) After waiting, start the car and let it idle without any load, lights, A/C etc.
6) Every 20 seconds or so the idle will be adjusted up and down as the ECU tries to adjust it towards a stoichiometric fuel / air mix.
7) Leave the engine running for a full 10 mins but DO NOT TOUCH THE ACCELERATOR during this time or turn on anything that will cause extra electrical current draw.
8) Turn off the engine, and leave the key in the OFF position for at least 20 sec.
9) As per step (4) turn the key back to the ON position for 10-15 sec without actually starting the engine.
10) Start the engine and leave to idle for a further 5 minutes without touching the accelerator and without turning on other systems in the car.
11) Turn off the engine again and wait at least 20 sec before restarting.
12) Take the car for a test drive as the ECU should now be fully retrained.
--------------
I know for a fact that this is necessary for the 2003 Forester XT because this process seems to have been the cause of all the teething problems with the LPG system because it was never retrained after the battery was disconnected during the conversion. I used an OBD2 adapter to measure the AFR beforehand - and the LPG AFR was waaay out in comparison to the petrol. After following the process above both sets of AFRs are now very close to a stoichiometric mix, and the car idles correctly without the revs bouncing up and down constantly.

This really made my day! Brought my Forester back to it’s normal acceleration condition! I followed every single step and it paid off. I am a living testimony that this guide works. Thanks again!

 

[2.5x_sleeper]

@Subfor16Jam welcome to the forum from Oregon!

Please complete your "Public Profile" - add your vehicle details!

Your forum "Public Profile" - how to fill this...

Welcome to the community! For the best forum experience, we recommend completing your "Account Details". The information you enter there will display when members click "About" in your forum profile. You can also create a custom "Signature" that will display every time you make a forum post...

www.subaruforester.org

Bobby...

['07 FSXT Member Journal] ['03 X Member Journal]

 

[paullind]

This sequence has worked for me just fine with the small exception :

At the final "START and let idle for 5 min".... I always have to give it a little accelerator to get the car to idle without dying. Once it goes- it will then idle and stay idling for the final 5 min..... then all seems to work and run fine. But it never seems to be able to just start and Idle on its own without dying without a little gas push at this step.

 

[2.5x_sleeper]

@paullind welcome to the forum!

Please complete your "Public Profile" ► add your vehicle details! ◄

Your forum "Public Profile" - how to fill this...

Welcome to the community! For the best forum experience, we recommend completing your "Account Details". The information you enter there will display when members click "About" in your forum profile. You can also create a custom "Signature" that will display every time you make a forum post...

www.subaruforester.org

Bobby...

['07 FSXT Member Journal] ['03 X Member Journal]