How-To Clear ECU Codes [Archive] - SaabCentral Forums

: How-To Clear ECU Codes


SpongeBob
24th March 2009, 12:30 PM
Just read an article which in part I cut and pasted below - does this also apply to our Saab ECUs ???
How-To Clear ECU Codes

1. Locate the ECU.
2. Turn the Ignition to the “On” position without starting the vehicle.
3. Locate the dial used to read and clear the codes.
4. Using a flathead screwdriver of proper size, rotate the dial clockwise until it stops. Wait one second and rotate completely counter-clockwise. If done correctly, error codes should flash on the dash. Use the combination of long and short flashes to determine the code. To reset the ECU, rotate the dial counter-clockwise until it stops. Wait one second and rotate it back to the original position. Remove keys, replace ECU in correct location, and enjoy the ride.

Well I have done all that I can do -
Brand new Mass Air Flow Sensor,
Working EVAP Solenoid,
New Intake Temp Sensor,
All elect. connections I could get to have been cleaned,
All Vac hoses have been checked,
Even after I disconnect/connect the battery and the CEL is off before re-starting I still get the same fault codes. I suspect that these fault codes are stored in the ECU memory and somehow have to be deleted. I have read a general article about performance upgrades in which it states that any change to the stock set-up the ECU detects as a fault and then goes into "safe mode" with much diminished performance - much the same as a desktop computer. The article suggests that the ECU must then be re-programed by TECH2. ---------- I don't know if the ECU has a seperate battery in it , like the CMOSS battery in a desktop or laptop which helps to store settings. If it did have such a battery then it would be a simple re-set by simply pulling it and re-inserting. I beleive that some Asian ECUs can be manual reset.

Darren900
24th March 2009, 12:33 PM
Just read an article which in part I cut and pasted below - does this also apply to our Saab ECUs ???
How-To Clear ECU Codes

1. Locate the ECU.
2. Turn the Ignition to the “On” position without starting the vehicle.
3. Locate the dial used to read and clear the codes.
4. Using a flathead screwdriver of proper size, rotate the dial clockwise until it stops. Wait one second and rotate completely counter-clockwise. If done correctly, error codes should flash on the dash. Use the combination of long and short flashes to determine the code. To reset the ECU, rotate the dial counter-clockwise until it stops. Wait one second and rotate it back to the original position. Remove keys, replace ECU in correct location, and enjoy the ride.
Again, where did you find this crap?

SpongeBob
24th March 2009, 12:49 PM
There's a lot of crap floating around --- can you tell me how to clear ECU codes? Just disconnecting the battery doesn't seem to work on my possessed 1995 V6 Saab.
Again, where did you find this crap?

Darren900
24th March 2009, 01:00 PM
There's a lot of crap floating around --- can you tell me how to clear ECU codes? Just disconnecting the battery doesn't seem to work on my possessed 1995 V6 Saab.
Fix the problem, pull the Motronic fuse, replace after a few minutes, then restart. If the CEL re-illuminates, then the condition is persisting.

You're correct that disconnecting power does not clear the code, but it does reset the CEL. To light the CEL, a new DTC has to be set as active. The only sure way to clear the DTC on your car is with the tech2.

SpongeBob
24th March 2009, 01:11 PM
Much appreciate advise --- what is tech2 - a reader? Not having a Saab dealer nearby, I did take the car to a Chevy dealer and asked for them to plug in their code reader - the service rep told me that it would cost $75 for them to do this and there would be no guarantee that their reader would even work on my Saab - he told me that most likely I need a European reader - I didn't want to spend $75 for nothing so I left.

Fix the problem, pull the Motronic fuse, replace after a few minutes, then restart. If the CEL re-illuminates, then the condition is persisting.

You're correct that disconnecting power does not clear the code, but it does reset the CEL. To light the CEL, a new DTC has to be set as active. The only sure way to clear the DTC on your car is with the tech2.

Darren900
24th March 2009, 01:34 PM
The Tech2 is the universal GM interface computer. It does everything possible.

Your dealer is an idiot and all dealers are crooks. It's typical that they charge $70-100 for "diagnostic" which means they plug in the tech2 and push 3 buttons. To interface your ECU, you need a tech2 with a Saab PCMCIA card and possibly a CAN-di module (not sure on the NG). Find a better GM dealer, or better yet a decent independent nearby. They're much better.

earthworm
24th March 2009, 01:46 PM
Not all dealers are crooks, maybe 10% are...its the rotten apple syndrome.....its also a laziness problem...

I do not think Tech 2 works effectively with OBD I.
After the problem, I'd just give the ECU plenty of time to erase the CEL by itsself... If this does not work, then I'd return to the OBD I process of jumping and bridging...
I do not accept the disconnect the battery concept...
OBD II is a different story....

SpongeBob
24th March 2009, 02:09 PM
What type of reader for the 1995 Saab 900SE with 2.5 V6 engine -- OBD1 or OBD2 --- It has 16 pins - 2 rows 8 each which is an OBD2 plug but I read somewhere that it's an OBD1 with an OBD2 plug. A local auto supply store has readers from $69. I'm confused if I buy the OBD1 it will not have the right connector --

john bernard
24th March 2009, 03:39 PM
The Gunson's fault finder is probably smilar to those $69. devices that were offered to you. It simply taps into one of the connectors on that 16 pin connector, and causes the check engine light to flash the codes which you read by counting the flashes.

Gunson's booklet has the following test notes:

Mass air flow sensor(hot wire sensor)

(with the ign on) 'probe the the airflow meter connector with a voltage meter until the sensor output is identified. The output will be a voltage of 0.5v to 4.5v or 4.5v to 9v.The voltage changes as the air flow is varied. The air flow can be varied by varying the engine speed. Test the output of the air flow meter with ign on, at idle, at 1500 rpm, at 3000rpm and during a rapid acceleration and compare to the typical values below
ign on .25v to 0.5
idle .5v to 1.5v
1500rpm 0.7v to 2v
3000rpm 1.1v to 3v
rapid accel. 3vto 4.5v

A sensor simulator can be used to provide a voltage to the ECU to simulatethe output of the air flow sensor and positively diagnose a faulty air flow sensor'
(note: the voltage values seem fairly broad and I'll check WIS and see if it gives narrower specs)

john bernard
24th March 2009, 04:21 PM
WIS provides the following MAF output voltage dataair flow in grams per sec. versus output voltage
0 g versus.1v
4g versus .8v
10g versus 1.2v
32g versus 2.2v
130g versu 3.9v

Since you do not have a means of measuring grams of air per sec, I'd substitute
ign on; idle; 1500 rpm;3000rpm; and rapid acceleration, but I am just guessing

Eric in Lockport, N.Y.
24th March 2009, 06:17 PM
technical data

http://i151.photobucket.com/albums/s152/1999saab93/massaf.jpg

http://i151.photobucket.com/albums/s152/1999saab93/massaf2.jpg

Eric in Lockport, N.Y.
24th March 2009, 06:33 PM
More testing options. The computer is in the passenger side kickpanel.

http://i151.photobucket.com/albums/s152/1999saab93/test1-1.jpg

http://i151.photobucket.com/albums/s152/1999saab93/test2-1.jpg

http://i151.photobucket.com/albums/s152/1999saab93/test3-1.jpg

http://i151.photobucket.com/albums/s152/1999saab93/test4-1.jpg

SpongeBob
24th March 2009, 09:05 PM
Check out this link - was told it should also work with Saab. Is it too good to be true?
http://www.aldlcable.com/sc/details.asp?item=aldlobd2u

Eric in Lockport, N.Y.
24th March 2009, 09:26 PM
None of the software seem to offer Saab support....:o

john bernard
24th March 2009, 10:47 PM
You apparently already have a means of reading the stored codes, and I think that is all these simple readers can do,ie, cause the CEL to flash. What would you gain?

SpongeBob
25th March 2009, 08:38 AM
Was hoping to be able to re-set the ECU.
I have no idea why the car is getting these fault codes -- all items that show fault have been replaced --- The only mods to the car is a K&n cold air intake system and an aftermarket catalytic.
You apparently already have a means of reading the stored codes, and I think that is all these simple readers can do,ie, cause the CEL to flash. What would you gain?

Darren900
25th March 2009, 09:20 AM
technical data

http://i151.photobucket.com/albums/s152/1999saab93/massaf.jpg

http://i151.photobucket.com/albums/s152/1999saab93/massaf2.jpg
Careful Eric. The Motronic 2.10.2 is for the 4 cylinder N/A engine. I believe it's a different version Motronic for the V6. The MAF may be the same, however.

john bernard
25th March 2009, 10:11 AM
Was hoping to be able to re-set the ECU.
I have no idea why the car is getting these fault codes -- all items that show fault have been replaced --- The only mods to the car is a K&n cold air intake system and an aftermarket catalytic.
The Gunson Fault Finder wont do anything but cause the CEL to flash the codes, I think the other devices are probably the same.

Eric in Lockport, N.Y.
25th March 2009, 10:20 AM
Careful Eric. The Motronic 2.10.2 is for the 4 cylinder N/A engine. I believe it's a different version Motronic for the V6. The MAF may be the same, however.

WHOOPS. I'll put the V6 charts on later tonight.....:cheesy:

john bernard
25th March 2009, 12:31 PM
I don't think there is much if any difference in the MAF in the 4cyl vs 6cyl. particularly in the context of SpongeBob's situation

Eric in Lockport, N.Y.
25th March 2009, 04:06 PM
IAT specs:

http://i151.photobucket.com/albums/s152/1999saab93/iat.jpg