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I've got a mess. 4 codes, Service Stabilitrak, Reduced Engine Power, Check Engin

84K views 39 replies 20 participants last post by  TomasA  
#1 ·
My wife was driving the car into work on Monday when all at once, "Engine Power Reduced", "Service Stabilitrak", as well as 'Check Engine' and 'Traction Control' lights came on. The code never cleared itself, and it hardly started once she got out of work to come home. At lower RPM's (1000-2500) the motor runs smooth. But when I give it more throttle to get up higher than the 2500-3000 RPM range, it starts cutting in and out like its starving for fuel. Anyhow, I got it scanned and got 4 codes:

p0172 Fuel Trim System Rich Bank 1
p0223 Throttle Position Sensor 2 Circuit High Voltage
p228c Fuel Pressure Regulator 1 Exceeded Control Limits/Pressure To Low
p00c6 Fuel Rail Pressure Low During Engine Cranking

I must mention that I just (3 days ago) got the car back from GM after having the oil consumption problem fixed by installing new pistons. Not blaming this problem on them, just wondered if it could have anything to do with it?

Also, Cruise Control says its set to whatever speed I'm at, but never actually sets. Not sure if this helps any at all. If this all has to do with fuel pressure, why does it say "Service Stabilitrak"?

Any ideas? I got a lemon as well :eek:hno:

Thanks guys and gals!
 
#2 ·
A low charge on your battery can result in many CEL codes being set. I would first check the battery, and if that is fully charged, then I would bring it to the dealer, and point the finger at them, since they touched it last.
 
#3 ·
I would suspect a faulty throttle body position sensor or something with the wiring for that system, especially after having the major repairs done. If the car idles well at low speeds but not at higher, there is something going on with the fuel delivery from what you say. Low battery wouldn't cause those symptoms I don't think but it won't hurt to have it checked out first.

The cruise won't set with a Check Engine Light on. Other systems will also turn on the lights such as Traction Control and Service Stabilitrak if certain other engine functions are not normal, even if it doesn't actually affect the traction or stabilitrak system as such. A leaky master cylinder code on the Enclave will set off the stabilitrak and traction lights as an example, as will a broken wheel sensor wire on most GM cars.
 
#38 ·
Low charged battery could most definitely cause these symptoms. If your battery is not putting out enough voltage then it would also follow logically that the engine would have reduced rpm's. Lower rpm's = Reduced High Fuel pressure.

The hp pump on the 2.4 Ecotec is mechanical and electrical. Mechanical because the piston is moved by the operation of the cam lobes and the electrical pressure sensor. If the sensor is bad youll have to buy the entire assembly. They dont sell the sensor sepa Have you ever heard of someone having a bad ground on the battery
I agree with JayTee. Try both of these. I'm not sure if either will work, but it's the most common ones.

1) Put the key in the ignition, and turn the key to the run position, but not start. Wait 3 seconds and turn it off. Repeat this 2 more times.

2) Put the key in the ignition, and turn the key to the run position, but not start. Slowly press the gas pedal all the way to the floor and let it up slowly. Do this three times.

Those are the most common throttle relearn methods. Since you've now got trouble codes and the power reduced message, you might need to start over by disconnecting the battery and resetting the computer. Throttle relearn is sometimes needed after a computer reset too.
Not on an equinox you dont. You start it and let it idle for 3 minutes. Shut it off and wait 10 minutes. Start again and run at idle 3 minutes. Shut off and wait 10 minutes. On the third part of the relearn you start the car and take it out on the highway for 10 minutes keeping plenty of distance between your car and the one behind you. The right lane is the best lane imo. You'll need to drive the speed limit for 1 minute and then alliw the car to naturally decelerate all the way diwn to 20 mph. This allows the transmission to shift down on its own and the ecm recognizes it. Yes, it is part of the relearn process. After you let it decelerate you'll take it back up to the speed limit and hokd for anothet minute. Repeat the deceleration process until it's been done a total of 3 times. It is at this point your system should be relearned. If nit repeat the entire process .
 
#4 ·
ls973800 said:
I would suspect a faulty throttle body position sensor or something with the wiring for that system, especially after having the major repairs done. If the car idles well at low speeds but not at higher, there is something going on with the fuel delivery from what you say. Low battery wouldn't cause those symptoms I don't think but it won't hurt to have it checked out first.

The cruise won't set with a Check Engine Light on. Other systems will also turn on the lights such as Traction Control and Service Stabilitrak if certain other engine functions are not normal, even if it doesn't actually affect the traction or stabilitrak system as such. A leaky master cylinder code on the Enclave will set off the stabilitrak and traction lights as an example, as will a broken wheel sensor wire on most GM cars.

Lots of good info here. Thank you for that. I am going to drop it off at GM tomorrow and they are going to work with me since they just did all the motor work. If it is something that has nothing to do with the repairs they just made, they'll let me know what the diagnosis is, and if simple, I will repair myself to save money. They have treated me very well thus far so hopefully everything works out! I will keep you all posted.
 
#37 ·
Thank you Thank you...absolutely fixed the problem changing the Throttle Body. My 2013 Nox service light came on "Stabilititrak" and very little power it was not drivable. Ordered the part from GMpartsdepot.ca for $120 had it within 2 business and replaced it easily took less than an hour my husband gave me the tools and was able to fix it myself.

Can't thank the forum enough, saved me a lot of money doing it myself and it was easy.

Carlene Szotak
 
#6 ·
Ralphalph said:
They just pulled your engine completely apart. High probability that this is likely related, maybe something was not put back together correctly. Get it back to the dealer.
I am taking it this evening, and they are looking at it first thing in the morning. I'm very eager to see if they'll accept responsibility or if they will say it wasn't related. Time will tell!
 
#10 ·
Not sure if this helps but as a point of reference for you all as this issue (similar if not the same flashing multiple messages and the vehicle would just slow down and then stop) happened to me one year ago at appx 74k miles. I don't have the code or codes from the diagnosis handy but it ended up that I needed the Throttle Body Replacement.
Vehicle is a 2011 Equinox LT1.
 
#11 ·
billydee said:
Not sure if this helps but as a point of reference for you all as this issue (similar if not the same flashing multiple messages and the vehicle would just slow down and then stop) happened to me one year ago at appx 74k miles. I don't have the code or codes from the diagnosis handy but it ended up that I need the Throttle Body Replacement.
Vehicle is a 2011 Equinox LT1.
Thanks! In case anyone in the future finds this thread like I did....

My issue started when I cleaned the throttle body. My 2010 Equinox (2.4L) had horrible acceleration and gas mileage and I found that the throttle body was coated in grime. I uninstalled it (not recommended apparently!!!!) to clean it. After it was clean and I re-installed, the code came on. P0223. Consequently my acceleration improved dramatically, but that was short-lived. Next thing I know it's telling me "Service Stabilitrak" and "Reduced engine power".

During my second test drive (this time on the highway) even though my foot was pressed all the way down, the car wouldnt go. Hooked up a scan tool to pull live data and everything looks normal, but my scanner doesn't have a PID for throttle position sensor - so I can't currently measure any data for it.

Long story short, after doing some digging on the internet I ordered a new throttle body and it should arrive tomorrow. I'll come back and update the thread with results.
 
#12 ·
Not sure, but I think after removing the throttle body, you are supposed to perform a calibration or "relearn" procedure.

Also, care must be taken not to over work or let the throttle plate snap shut or force it while cleaning it. Lastly, if not careful, you can spray too much TB cleaner into the pivot point on the actuator (motor) side of the inner bore. Care should be taken not to get TB cleaner forced into the motor assembly. I have read that some have damaged the motor by aiming too much spray into that point.

Here is a link to a pdf regarding a bit dated set of procedures for TB relearn. It is from 2009 and I think TB relearn procedure #4 may[/color] apply, but you might check into this more and try and find the exact procedure for your model and year.

LINK: . . .[/color]http://www.autocodes.com/uploads/gmc/throttle_body.pdf
 
#13 ·
I agree with JayTee. Try both of these. I'm not sure if either will work, but it's the most common ones.

1) Put the key in the ignition, and turn the key to the run position, but not start. Wait 3 seconds and turn it off. Repeat this 2 more times.

2) Put the key in the ignition, and turn the key to the run position, but not start. Slowly press the gas pedal all the way to the floor and let it up slowly. Do this three times.

Those are the most common throttle relearn methods. Since you've now got trouble codes and the power reduced message, you might need to start over by disconnecting the battery and resetting the computer. Throttle relearn is sometimes needed after a computer reset too.
 
#14 ·
Buggsy said:
I agree with JayTee. Try both of these. I'm not sure if either will work, but it's the most common ones.

1) Put the key in the ignition, and turn the key to the run position, but not start. Wait 3 seconds and turn it off. Repeat this 2 more times.

2) Put the key in the ignition, and turn the key to the run position, but not start. Slowly press the gas pedal all the way to the floor and let it up slowly. Do this three times.

Those are the most common throttle relearn methods. Since you've now got trouble codes and the power reduced message, you might need to start over by disconnecting the battery and resetting the computer. Throttle relearn is sometimes needed after a computer reset too.
+1. However, the pdf states not to do the procedure IF DTCs are present. So. . . not sure myself what he could try. Maybe clear the codes and try it?

Regardless, he should do the relearn if he buys a new TB.
 
#15 ·
Thanks everyone! Tried clearing the codes but theyre flagged as "permanent" codes and can't be cleared. I'm assuming this means when the issue is fixed it'll clear itself?

When it says " Do NOT perform this procedure if DTCs are set. " ....I hate to try to seem redundant or stupid (and I don't want to make anything worse than it is) but does it mean it'll break something if I try, or would it just not do anything effective?
 
#16 ·
Also, any scantool gurus in here? Conveniently I bought a scan tool earlier in the week to collect live data. After having this issue I selected all the PIDs that seemed relevant, and it looks like everything is in agreement. This was just a quick spin around my cul de sac:

http://imgur.com/2M5yP4i

I suppose my initial thought was that the throttle isn't actually opening, even though the computer "thinks" it's opening. However, because MAF increases I guess it means the throttle truly is opening. I'm a bit puzzled by this -- you think it could be an electrical issue?

Edit: Maybe I'm just thinking out loud at this point :eek: . I want to break it down in text and maybe it'll help me make sense of this. The facts:

(1) The MAP, MAF, Throttle, and Gas pedal all agree on what's happening. When I accelerate, the graph increases as expected.
(2) This debunks my theory that my throttle is stuck closed (hence restricting airflow and causing my little-to-no acceleration)
(3) The CEL code says "the voltage output from the Throttle/Pedal Position Sensor/Switch to the PCM is too high" which -and correct me if I'm wrong- means the throttle could be more open than it should be. So it still increases when I push the gas pedal, but it's baseline is just too high.

I'm wondering if "relative throttle position" and "absolute throttle position" might shed some light? The "absolute" value seems higher than I think it should be....but I really don't know.

http://imgur.com/5emkG8a
 
#17 ·
Maybe disconnect the TB again and check the connection for bent pins, etc.

Maybe check the MAP and any other connectors that you may have disconnected and check the pins. We had an '09 Saturn Aura with the2.4L mutil port FI engine and it had some fits of stabilitrak and loosing power. It turned out to be an intermittent connection at the BCM oddly enough. The dealer cleaned the connector and applied dielectric grease and never had a problem since.

I do not think it could make matters worse by trying the relearn procedure. . . especially one of the ones Bugsy listed first?

Did you disconnect the battery when you disconnected and cleaned the TB?
Those seem less invasive and complicated.
 
#19 ·
There are two throttle position sensors in the throttle body. What is happening when P0223 sets, the PCM is has detected that TP sensor 2 does not match TP sensor 1. If you have a GM scantool, you can view the throttle data. When you do a slow throttle sweep test, both sensors should display an "agree" data pid on the scantool. When that code sets it is a type a DTC, which means it will set as soon as the diagnostic runs and fails. When that code sets it will put the engine into reduced power mode. The only fix is to replace the throttle body. Unless you have a scope to compare the voltage, using a scantool voltage data pid is useless as it is too slow to update.

As far as doing a relearn, as soon as you turn on the ignition the PCM updates the minimum pedal and throttle position every time.

As far as the fuel codes, I would bet if the high pressure fuel pump was just replaced, it was not installed correctly using the special tool.
 
#20 ·
dfreas2010equinox said:
Thanks everyone! Tried clearing the codes but theyre flagged as "permanent" codes and can't be cleared. I'm assuming this means when the issue is fixed it'll clear itself?

When it says " Do NOT perform this procedure if DTCs are set. " ....I hate to try to seem redundant or stupid (and I don't want to make anything worse than it is) but does it mean it'll break something if I try, or would it just not do anything effective?
Permanent DTC's cannot be cleared by a scantool. The only way they will clear is when the diagnostic has run and passed in the PCM.
 
#21 ·
Update for all. Huge thanks to HFV6 for their wealth of knowledge. I purchased a cheap multimeter this morning and spent some time playing with it + my scantool to collect some data. Did some more research and went out and got a throttle body. Instant fix :D

Also I ended up finding the throttle relearn procedure for a 2010 Equinox. Hope this helps for anyone that doesn't have the repair manual.

1. Start and idle the engine in PARK for 3 minutes.
2. With a scan tool, monitor desired and actual RPM.
3. The ECM will start to learn the new idle cells and Desired RPM should start to decrease.
4. Turn the ignition OFF for 60 seconds.
5. Start and idle the engine in PARK for 3 minutes.
6. After the 3 minute run time the engine should be idling normal.

NOTE
During the drive cycle the check engine light may come on with idle speed DTCs. If idle speed codes are set, clear codes so the ECM can continue to learn. If the engine idle speed has not been learned the vehicle will need to be driven at speeds above 70 km/h (44 mph) with several decelerations and extended idles.

After the drive cycle, the engine should be idling normally. If the engine idle speed has not been learned, turn OFF the ignition for 60 seconds repeat the throttle learn procedure.
Once the engine speed has returned to normal, clear DTCs.
 
#22 ·
dfreas2010equinox said:
Update for all. Huge thanks to HFV6 for their wealth of knowledge.
Thanks, glad to hear that and glad to help.

HF
 
#23 ·
I am having this same issue Service Stabilitrak and Reduced Engine Power but the only code my 2012 terrain is giving is P228D which comes up as the fuel pressure regulator. Called the dealer got the regulator but I can not find the location on the car. Only other part I can think about is the fuel pump. Ive have asked the dealer and they claim its located on the fuel rail of the vehicle i have not been able to find it ... ANY IDEAS ??
 
#24 ·
SS86Monte said:
Ive have asked the dealer and they claim its located on the fuel rail of the vehicle i have not been able to find it ... ANY IDEAS ??
Which engine are you working on?