Resetting ecu advice

ad_car_08 · September 13, 2008, 12:16

Hi,

Just cleaned my MAF out of a matter o house keeping after I'd performed an oil change, but wish I hadn't...blummin yellow engine light is on now s:evil: :evil: s:evil:

I used the search function and found replies to say I could try taking the negative terminal off my battery for 30mins to reset the ECU, but i'm worried I'll need to input an immobiliser code on reconnecting the battery, or have alarm or radio code problems.
I haven't a clue where these codes are.....

So what i wanted to find out is if any of you had to pop codes in after reconnecting the battery??

philster_d · September 13, 2008, 12:20

I didnt and I have done mine loads of times. Also I think 30 mins sounds a bit long.

Wouldnt you want to read the engine code though? and actualy find if its a problem?

My car is turbo's so its to be expected I get the odd cat not efficient error and I know what it is.

Phil

ad_car_08 · September 13, 2008, 12:25

Hi philster

Taking in to account i woke up this morning, and drove to my parents house (problem free, no lights), then took the MAF off and cleaned it, replaced it and buttoned it back up, started the engine up and the light is now on, I can only assume it's MAF related.

I might just take it off and clean with electrical contact/cold start spray and give it another go.

Failing that, if 30mins is too long, how long should i keep the negative lead off for??

Anonymous · September 13, 2008, 12:31

where abouts are you.
You could always get a someone off here with a code reader to have a look for you

ad_car_08 · September 13, 2008, 12:33

Quote from: "DeeJ"where abouts are you.
You could always get a someone off here with a code reader to have a look for you

Telford, Shropshire

But i need to get to worcester at about 4..... eeeek!!!

Wabbitkilla · September 13, 2008, 12:58

You should always reset the ecu when cleaning the maf anyway.

Reset it, you've got noyhing to lose, it won't affect your radio unless it's an aftermarket one where the most you'll have to do is setup the stations again.
Don't panic, it's really not to worry about resetting the ecu

ad_car_08 · September 13, 2008, 13:11

Quote from: "Wabbitkilla"You should always reset the ecu when cleaning the maf anyway.

Reset it, you've got noyhing to lose, it won't affect your radio unless it's an aftermarket one where the most you'll have to do is setup the stations again.
Don't panic, it's really not to worry about resetting the ecu

I'm gonna hold fire on the ECU resetting JUST INCASE my '2 decides to play up! How long do I need to keep the neg off the battery to reset the ECU? Philster says 30mins is too long?

Just a quick update, took the MAF off, sprayed it with electrical contact cleaner, buttoned it back up, crossed fingers, and the engine light has gone out! Phew!!

philster_d · September 13, 2008, 16:09

I didnt say it was too long ?

I said it seems a long time to wait, a few mins is more than enough, but what do I know.

Anonymous · September 13, 2008, 18:02

The ECU will still hold a charge for a few mins, so half an hour sounds right to me. Mine used to take about 45 mins to reset.

ad_car_08 · September 14, 2008, 14:09

Sorry Philster, didnt mean to cause offence.

How do you know when your ECU has reset, if it can take between 30 - and 45mins?

Anonymous · September 14, 2008, 15:32

The CEL will be extinguished, for one.

kanujunkie · September 15, 2008, 08:32

you should always reset the ECU, it can throw a code as its seeing a drastic change in output from before it was cleaned

ad_car_08 · September 16, 2008, 11:22

Quote from: "kanujunkie"you should always reset the ECU, it can throw a code as its seeing a drastic change in output from before it was cleaned

Even though the light went out once I'd cleaned it for the second time?

Worth mentioning that I only cleaned the amber diode thingy, not the "resistor looking things" actually inside the MAF sensor, as I didn't have actual carb cleaner to hand & wasn't sure whether to risk cleaning the "resistor looking thingys" with electrical contact cleaner spray. Follow me? s:lol: :lol: s:lol:

kanujunkie · September 16, 2008, 11:35

the amber looking thing is a thermistor, the bit that senses the air temperature, the bit you really need to be cleaning is the platinum wire thats up the inside of the tube, the cel probably came on as the 2 sensors were reading different possible results and as such the system fails it as a malfunction, my guess is sheer dumb luck played a part and some of your cleaner splashed up inside and removed some of the possible dirt from the wire, thus putting the sensors back in tolerence with each other, these sensors are very sensitive and can be thrown out of wack pretty easily

ad_car_08 · September 16, 2008, 11:55

Whats an alternative to using carb cleaner?

I don't see the logic in buying a comparitively big can to spray two tiddly bits of wire - plus money is v.tight at the moment! s:oops: :oops: s:oops:

Anonymous · September 16, 2008, 14:39

If you can't afford a tin of carb cleaner then you can't afford a car, simple as. A tin is only a fiver.

ad_car_08 · September 17, 2008, 11:45

Grrr £5 for two quick squirts?! s:evil: :evil: s:evil:

SimonC_Here · September 17, 2008, 12:03

it's more than that around here s:oops: :oops: s:oops: s:wink: :wink: s:wink:

Simon

edward.carter · September 17, 2008, 12:16

halfords electrical contact cleaner £3.99 and best bit is its not just a couple of squirts, i had my can about 12-18 months, clean my maf once every couple of months or so.

now thats value for money! s:)

s:)

Anonymous · September 17, 2008, 13:26

Quote from: "ad_car_08"Grrr £5 for two quick squirts?! s:evil: :evil: s:evil:

Make it a regular thing then to keep your car running nicely (like we all should really), and do it every couple of months. You'll use a load more then if makes you feel any better, and you'll stop any dirty build up on the MAF at all.

ad_car_08 · September 17, 2008, 13:29

Going slightly off topic I guess, but what actually makes the MAF get dirty so quickly? I thought the filter...er..filters all the dust and nonesense, so the engine gets a supply of clean air??

I've not had to regularly clean the maf on previous cars i've owned?

More to the point, what am I/are we cleaning off the sensors? Mud/dust? Oil?
Is there something to look out for? e.g. oil on the MAF = a problem somewhere??

Anonymous · September 17, 2008, 13:37

Every filter is a compromise between filtration and actually letting some air through to allow the engine to work, so you'll always end up with tiny particles passing by and sticking to the hot wire on the MAF.

The colour of the thermistor is a relatively good idea as to how dirty the wire itself is, but that's as close as you'll get. And you don't have to regularly clean the MAF on the MR2 either, it's just a good idea as it was on all those other cars you've owned s;)

s;)