SaabCentral Forums banner

1 - 17 of 17 Posts

·
Registered
Joined
·
12 Posts
Discussion Starter #1
Related to another posting, I wanted to ask if anyone had any solid details on what occurs when going through this set of steps:

1) With the car off and key out of the ignition, put the accelerator pedal to the floor and hold it there.
2) Insert the key, turn to the on position, and start the car after the "Check OK".
3) Allow the car to start and idle normally, then take your foot off the accelerator pedal.

From what I understand this resets/re-calibrates the Throttle Position Sensor. I thought the 9-3 also had a learning function based on your driving habits, and I wanted to see if that may be the target of this process as well.

Does anyone have a definitive answer on what the above process achieves?
 

·
Registered
Joined
·
13 Posts
Related to another posting, I wanted to ask if anyone had any solid details on what occurs when going through this set of steps:

1) With the car off and key out of the ignition, put the accelerator pedal to the floor and hold it there.
2) Insert the key, turn to the on position, and start the car after the "Check OK".
3) Allow the car to start and idle normally, then take your foot off the accelerator pedal.

From what I understand this resets/re-calibrates the Throttle Position Sensor. I thought the 9-3 also had a learning function based on your driving habits, and I wanted to see if that may be the target of this process as well.

Does anyone have a definitive answer on what the above process achieves?
I just tried this, my car won't fire like that. It cranks, but won't actually start.
2006 9-3 V6 Aero. Stage 0 tune.
MY TP says 23% with no pedal down, and maxes at 87.6% at full throttle. Could be worse, but I'd love to adjust it.
 

·
Registered
Joined
·
391 Posts
Does anyone have a definitive answer on what the above process achieves?
It achieves nothing. Well, technically, you get your pedal sensor recalibrated for min and max positions, but that happens every time you turn the ignition on anyway.

As for the throttle position sensor, recalibration is not necessary by its architecture.

Both Trionic 8 (4cyl petrol) and Motronic E9 (v6) ECMs calculate torque request according to different modificators (e.g. pedal position, temperature, current RPM, etc.), convert it to a required TPS voltage value and use PWM motors to rotate the throttle until TPS reports a requested position.

There are two potentiometers in the throttle used to get and verify throttle position. If they are disagree for any reason, i.e. the sum of voltages on them is not a 5V, ECM assumes that TPS is failing and car goes to limp home mode. Otherwise, ECM just trusts to first potentiometer readings.


MY TP says 23% with no pedal down, and maxes at 87.6% at full throttle. Could be worse, but I'd love to adjust it.
WIS says that's fine. The throttle is opened slightly by a spring by default and never opens up to a maximum theoretical value.
 

·
Registered
Joined
·
1 Posts
I just tried this, my car won't fire like that. It cranks, but won't actually start.
2006 9-3 V6 Aero. Stage 0 tune.
MY TP says 23% with no pedal down, and maxes at 87.6% at full throttle. Could be worse, but I'd love to adjust it.
"There are two potentiometers in the throttle used to get and verify throttle position"

Do you know what might cause the potentiometers to get out of whack? I have a 2005 2.0L 9-3 that has been having this issue off-and-on for the last 20K miles. I've replaced the pedal, throttle body, and wiring between the two. My tech has confirmed that the voltage difference is what keeps triggering limp home mode, but neither he nor two other mechanics I have spoken to can do anything but guess at what is causing the issue.
 

·
Registered
Joined
·
391 Posts
"There are two potentiometers in the throttle used to get and verify throttle position"

Do you know what might cause the potentiometers to get out of whack? I have a 2005 2.0L 9-3 that has been having this issue off-and-on for the last 20K miles. I've replaced the pedal, throttle body, and wiring between the two. My tech has confirmed that the voltage difference is what keeps triggering limp home mode, but neither he nor two other mechanics I have spoken to can do anything but guess at what is causing the issue.
There's no wiring between the throttle body and the pedal. Both are connected to the ECM separately.

In my case the problem was in the throttle body connector. It has never been disconnected for 10 years, so got some oxidation eventually. Cleaning it up with a DeoxIT fixed the issue. In your case you may also want to visually inspect all pins in the connector. Sometimes they can get out of place or have a weak clamp and cause a bad contact.
 

·
Registered
Joined
·
3 Posts
Hi - Quick question - as part of your symptoms did your cruise control stop working ? I’m assuming that once limp home mode is triggered cruise light won’t even come on.
 

·
Registered
Joined
·
3 Posts
Fixed...

Hi - as a matter of fact my car is running perfectly well right now with no issues related to the hesitation/ cruise , CEL and TB symptoms. What a confusing issue to deal with...... I actually had ordered a new Throttle Body (used on EBay)but in the meantime I took the old one off, cleaned the contacts with electronic parts cleaner, took the throttle pedal out of the car and again cleaned the connectors with the parts cleaner and I also took the cruise/ direction indicator stalk off the steering colum and cleaned it....... voila , everything worked as it should....... I’m stupid for ordering a new TB and still have it as sparemin case down the road I’ll need it but it seemed the only thing I did was clean the contacts ...... but I really don’t know if that was the problem , but fingers crossed all is good.
Hope yours is now working too.
 

·
Registered
Joined
·
53 Posts
It achieves nothing. Well, technically, you get your pedal sensor recalibrated for min and max positions, but that happens every time you turn the ignition on anyway.

As for the throttle position sensor, recalibration is not necessary by its architecture.

Both Trionic 8 (4cyl petrol) and Motronic E9 (v6) ECMs calculate torque request according to different modificators (e.g. pedal position, temperature, current RPM, etc.), convert it to a required TPS voltage value and use PWM motors to rotate the throttle until TPS reports a requested position.

There are two potentiometers in the throttle used to get and verify throttle position. If they are disagree for any reason, i.e. the sum of voltages on them is not a 5V, ECM assumes that TPS is failing and car goes to limp home mode. Otherwise, ECM just trusts to first potentiometer readings.



WIS says that's fine. The throttle is opened slightly by a spring by default and never opens up to a maximum theoretical value.
Hi

for the 2003 9-3 what does the throttle body connect to seems to be a sensor what is it I spilt some coolant on it by accident and car not starting right
 

·
Registered
Joined
·
3 Posts
"What car?"
Sorry...2006 9-3/2.0 T.
Stammers at idle, accelerates very well and then at cruise control(Interstate speed), it's back to stammer.
 

·
Registered
Joined
·
6,036 Posts
Related to another posting, I wanted to ask if anyone had any solid details on what occurs when going through this set of steps:

1) With the car off and key out of the ignition, put the accelerator pedal to the floor and hold it there.
2) Insert the key, turn to the on position, and start the car after the "Check OK".
3) Allow the car to start and idle normally, then take your foot off the accelerator pedal.

From what I understand this resets/re-calibrates the Throttle Position Sensor. I thought the 9-3 also had a learning function based on your driving habits, and I wanted to see if that may be the target of this process as well.

Does anyone have a definitive answer on what the above process achieves?
generally holding the gas pedal down all the way on an efi or gdi engine shuts off fuel on start up.
 

·
Super Moderator
Joined
·
19,207 Posts
"What car?"
Sorry...2006 9-3/2.0 T.
Stammers at idle, accelerates very well and then at cruise control(Interstate speed), it's back to stammer.
Sounds like unmetered air is getting in after the maf. Inspect hoses. vacuum, air, etc
 
1 - 17 of 17 Posts
Top