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Penrod 04-04-2014 08:31 PM

Throttle Position Relearn
I was messing with my throttle body and think I need to adjust it. After looking at other posts I've came to the conclusion that my ECM needs to relearn the throttle idle. Does anyone know how to perform this, or do I need special equipment? I own an 09 Saturn Outlook and have codes P0122 and P0223. I also have the traction control disabled and reduced engine power messages. Any information would be helpful. Thanks.

fdryer 04-04-2014 11:49 PM

Re: Throttle Position Relearn
Which engine? Fwd or awd?

Penrod 04-05-2014 11:27 AM

Re: Throttle Position Relearn
3.6 fwd

fdryer 04-05-2014 04:39 PM

Re: Throttle Position Relearn
A partial reprint from the service manual; (no tools needed)

[I][U]Throttle Body Relearn Procedure[/U]

The engine control module (ECM) stores values that include the lowest possible throttle position (TP) sensor positions--0 percent, the rest positions--7 percent, and the return rate of both springs. These values will only be erased or overwritten if the ECM is reprogrammed or if a throttle body relearn procedure is performed. Observe, if the battery is disconnected, the ECM will immediately perform a throttle body relearn procedure when the ignition is turned ON.

A throttle body relearn procedure is performed anytime the ignition is turned ON, with the engine OFF for longer than 29 seconds. After 29 seconds, the ECM commands the throttle plate from the rest position to full closed, then to around 10 percent open. This procedure takes about 6-8 seconds. If any faults occur in the throttle actuator control (TAC) system, a DTC sets. At the start of this procedure, the scan tool TAC Learn Counter parameter should display 0, then count up to 11 after the procedure is completed. If the counter did not start at 0, or if the counter did not end at 11, a fault has occurred and a DTC should set.

DTC P0121-P0123 or P0221-P0223

DTC P0121: Throttle Position (TP) Sensor 1 Performance

DTC P0122: Throttle Position (TP) Sensor 1 Circuit Low Voltage

DTC P0123: Throttle Position (TP) Sensor 1 Circuit High Voltage

DTC P0221: Throttle Position (TP) Sensor 2 Performance

DTC P0222: Throttle Position (TP) Sensor 2 Circuit Low Voltage

DTC P0223: Throttle Position (TP) Sensor 2 Circuit High Voltage

[U]Circuit/System Description[/U]

The throttle body assembly contains 2 throttle position (TP) sensors. The TP sensors are mounted to the throttle body assembly and are not serviceable. The TP sensors provide a signal voltage that changes relative to throttle blade angle. The engine control module (ECM) supplies the TP sensors with a common 5-volt reference circuit , a common low reference circuit, and two independent signal circuits. The TP sensors have opposite functionality. TP sensor 1 signal voltage decreases from greater than 4 volts at idle to less than 1 volt at wide open throttle (WOT). TP sensor 2 signal voltage increases from less than 1 volt at idle to greater than 4 volts at WOT. [/I]

Our drive by wire systems uses the electronically controlled throttle and pedal coupled to the ecm as a three part system. Dual feedback circuits in throttle and pedal ensure 100% safety otherwise the reduced power mode is invoked to prevent any engine runaway issues from occurring. All electrical connections must be clean and free of corrosion in their weather proof boots to ensure low voltage feedback circuits maintain constant communications for trouble free reliability.

If reduced power occurred, the usual problems are either throttle or pedal as they're the moving parts with external sensors and motor to wear down. Wiring and connections can also contribute to problems. Try the relearn procedure. Normal throttle operation; with ignition on throttle plate movement should mimic pedal travel.

Penrod 04-05-2014 07:05 PM

Re: Throttle Position Relearn
As soon as I turn the key on the throttle plate goes through the movement and doesn't go through the relearn process at 29 seconds. I'm pretty sure I took the throttle body sensor apart further than I was supposed to, but now I'm getting the idle relearn code. Before I actually replace the throttle body assembly, is the throttle plate movement supposed to happen right away or is it supposed to wait the full 29 seconds? The throttle plate also doesn't mimic the pedal movement with the key on/ engine off.

fdryer 04-05-2014 08:23 PM

Re: Throttle Position Relearn
At ignition ON time, all electronics go thru their power-on self tests then the throttle is preset to an initial opening based on temperatures for rich, normal, lean fuel mixtures. Ignore this throttle setting. The 30 second delay without pressing the pedal is detected by the ecm to invoke the throttle calibration routine. The most important observation of all this is that you can't move throttle when pressing pedal; this is strictly a master/slave relationship of drive-by-wire systems - pressing pedal is supposed to result in throttle plate opening in direct proportion. Its presumed ignition is ON as powering off turns off electronics.

Cleaning electric/electronic throttles that are not completely sealed from solvents may cause problems if solvent works its way inside and causes electrical problems. Solvent that conducts electricity may temporarily short out circuitry and cause more problems. Service manuals caution against excessive solvent use. While its said that there are no serviceable parts inside, taking on any task to disassemble and examine/clean/repair anything in these throttles also carries another risk; electronically controlled throttles are precision devices requiring caution in handling as the repercussions can't be explained with a worse case scenario of a botched disassembly/examination/cleaning/repair - an uncontrolled engine.

Penrod 04-05-2014 08:46 PM

Re: Throttle Position Relearn
I figured I messed it up because I didn't have any of these issues till I tinkered with it. I ordered a new throttle body assembly and will see if that fixes my current issues. I'll update this thread when I change it out. Thanks for all the help that you have provided so far.

Penrod 04-11-2014 09:15 PM

Re: Throttle Position Relearn

I replaced the throttle body assembly and it fixed all my issues. The wife test drove it and said there's another issue with the vehicle stuttering and not going over 20 mph. I'll take it out later and verify and see what I come up with. Thanks fdryer for your help with this, I'm sure you'll be giving more advice as I run into issues.

wubba68 04-22-2014 11:11 AM

Re: Throttle Position Relearn
If your wife is refering to the engine reduced power mode and traction controll is turned off, My wife's 07 XR was having the same issue and I replaced the gas pedal with the TPS sensor on it and it has been two weeks and no further issues with it. You may want to try that part was $80 dollars online.

Penrod 04-23-2014 08:06 PM

Re: Throttle Position Relearn
The throttle body assembly fixed it.

fdryer 04-23-2014 08:35 PM

Re: Throttle Position Relearn
Excellent! If possible, if the throttle actuator is apart, mind posting pictures? I've kept my meddling fingers off my throttle actuator when replacing a stubborn t-stat a few years ago. I was intrigued when a member from Alaska opened his throttle actuator on his 3.0L Vue after replacing it with a used one from ebay. His only remarks were that there are familiar parts within that [I]may[/I] be serviceable. I'm not tempted to play with mine unless absolutely necessary and/or have a back up in case failure occurs.

Thank you for following up. :cool:

Penrod 05-25-2014 02:19 PM

Re: Throttle Position Relearn
Sorry it took so long to repost. After searching for the throttle position assembly I think I my have thrown it away. If I do come across it I will post pictures.

Gritsngravy711 07-14-2015 09:46 PM

Re: Throttle Position Relearn
So, I am also having a problem with my drive by wire system as well. I was getting an error code of p2135 so I replaced my throttle body. It was used. When I first installed it appeared to have fixed the didn't have to run a relearn procedure I just disconnected the battery. A few days later, it started going in to low power mode.most of the time it does it, sometimes it doesn't.I've tried the above procedure to do a relearn but to no avail. Any suggestions?

Penrod 07-15-2015 08:21 PM

Re: Throttle Position Relearn
It my be the pedal sensor. If you have the ability to swap that out you could give it a shot. I've only disconnected the connector from mine, not completely replaced it.

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