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Discussion Starter · #1 ·
Hey guys,
It seems this is a common problem.I have a 2007 Impala LT with about 107,000 miles. (All highway driving). Out of no where, while driving, the display says "Engine Power Reduced" and then switches to "Service Traction Control". Then just like everyone has stated, I have limited power, the check engine light comes on and so does the traction control light. I can drive the car to where I am going, but no acceleration. I shut the car off and a few hours later after I start it again, only the check engine light is still on, but no more messages and the car runs fine. About a day or two later when I start the car even the check engine light is off. No problems or messages, car runs fine. About a week of driving goes by and the whole thing happens all over again at some random time, then clears itself again.
Any advice to what the problem/fix would be? Also, if I go to the dealer and the lights are off with no messages, can they diagnose the problem? Is there a memory in the computer for past codes or does it have to be actually happening? Thanks for any help/advice.
I really prefer a big block with no computer and a carburetor!
 

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Mr. Handy
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I am not all that familiar with these cars but, to me it sounds like you have a faulty ABS harness, sensor, or possibly moisture in the abs connection.

Yes the codes are stored and the dealer should be able to view them.

Personally: I would take all the wheels off and inspect the abs harness's to each wheel. Check for binding or cracked wires. Then, remove the connector going to each hub and use compressed air and a small brush to clean the contacts. Then, apply a few dots of dielectric grease (bought at any auto store) to each terminal. This will keep moisture out.
 

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8th Gen Antagonist
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Definitely get that code read, if it turns up a p2135 I think it was, you need to replace the throttle body. Of course check the code first though and post it here.
 

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Mr. Handy
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^^ Wow a throttle body issue on these 8th gens will cause the "Service Trac control" to appear? I did not know
 

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8th Gen Antagonist
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Thats more secondary to the "reduced engine power" issue, it shuts down everything and goes into fail safe mode. I'm not saying necessarily that is what is going on here, just a possibility.
 

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Mr. Handy
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^^ Gotcha
 

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Discussion Starter · #7 ·
Thanks for the advice. I am a little confused though. Why would the message about the "Traction Control" come up if it is related to the throttle body? I may replace the throttle body anyway (most guys here say it's cheap enough and very easy to replace). I would think that ANY problem would trip the "reduce engine power". Like you said, it is the failsafe default for any of the vehicles failures/conflicts. But that would be the secondary step AFTER the computer detects a primary problem. In this case the traction control.
Not sure if that makes any sense but that's the way I would think-- but maybe not the computer on these cars!! Thanks again for your input!!
 

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8th Gen Antagonist
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I'm thinking traction control gets disabled BECAUSE of the reduced engine power/limp mode. You can replace the throttle body if you want, it is extremely easy, but its close to $300, which to me is far from cheap. I would get that code read first.
 

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Discussion Starter · #9 ·
I just had the car scanned and the display says "Throttle Position Sensor" is the problem. Going to order one and put it in to see if that fixes it.
 

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8th Gen Antagonist
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Throttle body, the TPS is integrated, can't be purchased separately. Fortunately, it doesn't need to be programmed on these cars, it's plug and play.
 

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Discussion Starter · #11 ·
Well, you can buy the "throttle position sensor" separately. I ordered one online for $60 and installed it in about 15 minutes. It's very easy to do. It mounts on the side of the throttle body with 6 clips. If you do order the entire throttle body (for $135), the throttle position sensor is included. I did the install and everything seemed OK for about two days, then all the warnings and reduced power again!!! So this time I went to another shop, they scanned it and told me '"throttle position sensor" again. BUT, then the guy laughed and said "yeah, we used to call that a gas pedal". Holy cow! Just like on my other car the "fly by wire" gas pedal (sensor) went bad. So I ordered the accelerator pedal assembly on line for $65. Installed that in about 5 minutes (two bolts and plug it in). So far, all is well after a week. Just one last question: The check engine light is still on. Thought it would go off after some good input into the computer while driving. Does it need to be reset? or how long will it take to reset itself? Thanks!
PS While I had the TPS off the throttle body I took a look at the white plastic gear that so many people say goes bad or gets stripped. It looked OK.
 

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8th Gen Antagonist
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My gears looked fine too, but replacing it still fixed it. The code for the pedal should be different than the code for the tps, should say sensor input or something like that. Where did you get the parts? When I purchased only the dealer had anything, and it was only the entire TB you could get.
 

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Discussion Starter · #13 ·
Been driving awhile to see what would happen... I get my parts from Rock Auto. They always have a good selection and their prices are usually 20% less than the auto stores. They had all the parts sold separately. --- So the "check engine" light is still on, but the car runs fine and no error messages. I went and had it scanned again. Now it says "Canister Vent Valve Solenoid". The code is P0449. I can get that too for about $45. It is an easy access/install part next to the gas tank under the car. I probably will do it. They said it could also be a bad Vapor Canister or Canister Purge Valve. Where are these located??? Thanks!
 

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8th Gen Antagonist
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You should be able to clean and lube the canister vent, that usually gets them working again. The purge valve is located on top of the engine.
 

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Hey Guys where do you go to have the codes read? I have a little pocket one that shows no codes on my 03 impala but I am have issues with the traction control coming on when i first pull out of the driveway and now today my dash lit up like a firework show with abs, traction control off and service traction control on the display. Turn car off to do errands and it all went away but now I notice my abs coming on sometimes when i go to stop. That could be a little dangerous if or when i may need to slam on them and it doesn't allow me to brake hard. Does the dealer cost to read codes?
 

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Mr. Handy
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Call around to part shops. Ask if they have an "abs capable obd scanner". Some parts places don't have abs capable so, I would call and ask before wasting gas.

It's likely the front harness's if it's an intermittent problem. The stock front harness's have a manufacture's defect. The wires get pinched by the hold downs on the control arms.

Test by turning key to on position. Hook up a volt meter to the abs harness. Read/monitor voltage while wiggling the harness. It should stay a constant 5vdc.

Note: When getting codes read it will tell you which wheel is throwing the code. But, just b/c the scanner says Front Left hub sensor or w/e does NOT necessarily mean it's the abs sensor. B/c the sensor doesn't get the correct voltage your computer thinks it's the hub. Just saying I have seen plenty of people start replacing hubs when all it was is the harness. You can buy pigtails on rockauto and splice them in.

Edit: You really should have made a new thread for this. Mod: Feel free to move his comment and mine as well to a new thread.
 

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Hi Guys,
In May I had the traction control light coming on as well as the abs light and the check engine, traction control light. One day it was like fireworks going off on my dash, errrr. So I took my FR wheel of and took apart the abs hub sensor connector and cleaned out the connectors with compressed air and put everything back together tightly. All was pretty quite for about a month and a half but now I am getting my traction control light usually when I first back out of the driveway and turn to the left. Sometimes when I leave a stop light it will go off too but almost always when first coming out of the drive way. Now when I had everything apart I put a volt meter on the connector and got 5vdc consistent on the hardness wire and moved it around and tapping on it and not a loss or change of the 5vdc. I got 1176 ohms for the hub side of the wire. Everything seems to be in spec. Since its just the traction control light coming on now do you think its the wheel speed sensor not working correctly or dirt or grim on that axel groove thingy that the sensor reads? I had a new transmission put in in February do you think its something they did? Also when I took everything apart i felt a very minute shake in the wheel but I don't think that would cause enough vibrations especially since i am not going that fast when the traction control light comes on. Also the hub or bearings or not making any kind of noise, so thats why i am trying not to replace it.

Thanks in advance
 

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Engine Power Is Reduced 2006 Chevy Impala

Last week during the holidays I took a vacation to visit my family in Atlanta from Knoxville Tennessee with no problems.Then on Friday night January 4, 2013 on my way home the engine light came on, I stopped and got groceries and made it home OK. Went on my way to work this past Saturday January 5,2013 and got a message before I even got a mile from my house going uphill that said "Engine Power Is Reduced" on my dashboard and the car immediately went from 40 miles per hour to completely shutting off while in drive mode. I continued on a few minutes later and pulled into the nearest gas station and filled up. But to my dismay it happened again and I took a side road to get back to my house and called my job to see if there was anyone who lived near me that I could carpool with to get to work. The car is now in my driveway and I am afraid to drive it. Can someone please tell me what to do? I have never had a car to do this before and afrid that at some random time this will happen again and I could be in a serious accident while driving in traffic with other around me and also directly behind me. Thanks a bunch!
 

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I would do that but I am afraid to drive the vehicle at this point due to the nature of the situation .Which now places myself, passengers in my vehicle and other drivers on the road at risk with a vehicle that is unsafe and unreliable for driving right now.However I sincerely thank you for this advice jtrotsky.I was always taught that when it comes to driving to " Be safe and watch out for the other guy." But the flip side to that is "Remember that you also are the "other guy".
 
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