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I am new to the forum, so forgive me if I don't quite know how to do this! I have a 2006 GTP with about 91K miles. Here recently the traction control indicator would come on (as if I turned off the traction control). Then later on the check engine light would come on intermittenly. After a few trips to the dealership, they said that the fuel injectors were dirty and needed cleaning. So this was done and for a bit seemed ok... Then the traction control light would come on again, and then CE light. Then it I began to feel rough idle and what to me seemed like a miss when I accelerated. So back to the dealership again.. and this time they say that after contacting GM they say the injectors are bad... So have new injectors and can see improvement in how it runs, but the traction control light still comes on.. :mad: I have had different people tell me that the two are not related but then some say that they are. The ABS light has never come on, so I didn't think it was a wheel sensor... would love to hear if anyone has experienced this issue!!! thanks! and yes, I love my G6:D
 

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I've had the same problem recently.I took my car to a mechanic and had a diagnostic test ran and the Camshaft position sensor and the MAP sensor was out.I changed both and the car seems to be running fine.From the research ive done its a cause of the wiring on the car.the wires are ran to close or ontop of the engine causing them to melt and ground out.Afaulty ground will cause the sensors to go out which causes the trac control light to come on and make the car shift hard.If the check engine light is on you can go to autozone and have them put it on a computer reader and get the code.If not you have to go to the dealer or a machanic with a comp diagnostic test machine to find out which sensor is bad.so far with mine its electrical not machinical.
 

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ongoing issues...

Well, now the CEL is back on (though not all the time). I had a computer put on it and it gave the code P0174. Since I have had the fuel injectors replaced, I know that's not the issue... It said that it could also be O2 sensor Bank 2 - sensor 1. Could anyone tell me where that one is located? Is it in front or or in the back of the converter? :mad:
 

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I am new to the forum, so forgive me if I don't quite know how to do this! I have a 2006 GTP with about 91K miles. Here recently the traction control indicator would come on (as if I turned off the traction control). Then later on the check engine light would come on intermittenly. After a few trips to the dealership, they said that the fuel injectors were dirty and needed cleaning. So this was done and for a bit seemed ok... Then the traction control light would come on again, and then CE light. Then it I began to feel rough idle and what to me seemed like a miss when I accelerated. So back to the dealership again.. and this time they say that after contacting GM they say the injectors are bad... So have new injectors and can see improvement in how it runs, but the traction control light still comes on.. :mad: I have had different people tell me that the two are not related but then some say that they are. The ABS light has never come on, so I didn't think it was a wheel sensor... would love to hear if anyone has experienced this issue!!! thanks! and yes, I love my G6:D
Hi Lefty300:

I also have a 2006 GTP (mine only has 35K miles) that has recently developed virtually exactly the same problems you describe.

1. TC-Off light starts coming on, upon moderate to heavy acceleration, after about driving 10 miles. Shifts hard when light is on. Light goes out when acceleration is discontinued.

2. Has set either DTC P0171 or P0174 (lean, but on different banks) during the last three >100 mile trips on the highway. SES light went off by itself after multiple ignition cycles over two days in one case. The other two times I had the codes read and cleared at Advance Auto Parts.

I am an ex-Pontiac Technician who did these types of problems (admittedly back in the 80's and early 90's) - so I'm familiar with, but not up to speed on OBD2 and the new systems.

Problem with many technicians/dealerships/shops, is if they don't want to take the time to (or don't have the skills/equipment to successfully) diagnose the problem - they will take a guess and throw a part or parts at it. Hence your fuel injectors. FYI - oxygen sensors have always been the most replaced emissions item that usually fixes nothing.

I am in process of researching this problem/fixes that make sense to me (on various places on the Internet. As you can see - there are very few problems that are unique to one vehicle (since we have the same problem). I also have a full set of factory shop manuals, but no scan tool of my own - so diagnosis per the manual is a bit troublesome when it calls for the scan tool.

From what I have read so far - the TC light and hard shifting seems to be the result of poor (intermittent) engine performance. Off the top of my head, MAF sensor issues (as stated both elsewhere in this forum and elsewhere on the Internet) makes sense to me for both the codes and the poor intermittent performance. I've already given mine a cursory look-over for vacuum leaks. Going to see if cleaning my MAF sensor will fix the problem.

If I get it figured out I'll post. Please do the same if you have success.

LMyer
 

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Removed the MAF sensor from the car for inspection. It did not appear to be dusty or dirty, but I sprayed it down good through both ways with CRC MAF Sensor Cleaner and let dry for 5 min. Installed back in the car along with new air filter (old filter one was not really bad yet, but put a new one in anyway). Test drove for 1/2 hour and I could not get the TC-Off light to come on during acceleration (it seems to be fixed). Also appears to idle a little better and have a little more snap from idle. Admittedly - all of this could just be wishful thinking. I'll know for sure in a few days, as the TC-Off light has been a daily observable problem and the weather is supposed to be exactly the same.

ps to Lefty300. I found in my service manual where they say the TC-Off light problem is linked with various codes including P0171 and P0174.

LMyer
 

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Well, now the CEL is back on (though not all the time). I had a computer put on it and it gave the code P0174. Since I have had the fuel injectors replaced, I know that's not the issue... It said that it could also be O2 sensor Bank 2 - sensor 1. Could anyone tell me where that one is located? Is it in front or or in the back of the converter? :mad:
Lefty300:

First clean your MAF sensor if you have not. If that doesn't help (& it probably won't but its just good maintenence), you may have an intake air leak downstream of the MAF that is allowing unmetered air into bank 2. A smoke machine leak test can generally find leaks pretty fast.

Your statement "Then it I began to feel rough idle and what to me seemed like a miss when I accelerated" leads me to suspect an intake air leak.

Don't be in a hurry to replace any of the O2 sensors.

Which engine in that car?
 

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Removed the MAF sensor from the car for inspection. It did not appear to be dusty or dirty, but I sprayed it down good through both ways with CRC MAF Sensor Cleaner and let dry for 5 min. Installed back in the car along with new air filter (old filter one was not really bad yet, but put a new one in anyway). Test drove for 1/2 hour and I could not get the TC-Off light to come on during acceleration (it seems to be fixed). Also appears to idle a little better and have a little more snap from idle. Admittedly - all of this could just be wishful thinking. I'll know for sure in a few days, as the TC-Off light has been a daily observable problem and the weather is supposed to be exactly the same.
LesMyer:
In your case having both 171 & 174 (both banks running over lean) a dirty MAF sensor could account for that. A dirty MAF sensor can't correctly meter the incoming air quantity so it sends bad input to the ECM/PCM. If only one bank reports as lean, generally it's not a MAF sensor issue. Having a scan tool that reads real-time fuel trim data is very helpful/necessary in diagnosis. They can be had for a couple hundred bucks now. I use ScanXL with enhanced GM add-on on a laptop.
 

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LesMyer:
In your case having both 171 & 174 (both banks running over lean) a dirty MAF sensor could account for that. A dirty MAF sensor can't correctly meter the incoming air quantity so it sends bad input to the ECM/PCM. If only one bank reports as lean, generally it's not a MAF sensor issue. Having a scan tool that reads real-time fuel trim data is very helpful/necessary in diagnosis. They can be had for a couple hundred bucks now. I use ScanXL with enhanced GM add-on on a laptop.
Thanks for the recommendation on the Scan tool. If the problem returns I'm sure I will be buying something like this (rather than paying a dealer for diagnosis/repair). But hopefully I made a lucky guess on my problem. Time will tell.

Please advise if in your experience this software allows full function and control of the OBD2 system as required by the factory manuals for diagnosis.

Thanks,

Les Myer
 

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Please advise if in your experience this software allows full function and control of the OBD2 system as required by the factory manuals for diagnosis.
No, it won't. There is no substitute for the dealer's tech 2, unfortunately. And that's the way they like it.
 

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Discussion Starter #11
I have a 3.9L V6 engine... it's been a great car.. and I'm actually thinking of selling it and getting a G8. But until then, I am hopeful I can get this thing taken care of. Would not want to sell to someone with this issue going on.

I will be checking out all the suggestions on here... and if you (or I) find out the issues... I will post asap!:)
 

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I have a 3.9L V6 engine...
The traction control lamp will go out after you resolve the p0174 code. The EBCM shut off the traction control system in response to that code popping.

So pretty much all I know about your car is that you have an over-lean condition in bank 2. Either you have too much air or not enough fuel in bank 2. Since you don't have any other codes set, an intake air leak past the MAF & affects only bank 2 is a prime suspect. But there are many other possibilities. I suspect you will need help sorting it.
_______________________________________________________
Circuit/System Testing For DTC P0174
• Allow the engine to reach operating temperature. With the engine running, observe the Long Term FT parameter with a scan tool. The value should be less than approximately 19.5 percent with the engine running at operating temperature.

• If the value is not less than 19.5 percent, inspect for the following:

- With the ignition ON and the engine OFF, observe the manifold absolute pressure (MAP) sensor parameter. The MAP sensor pressure should be within the range specified for your altitude. Refer to Altitude Versus Barometric Pressure .

⇒ If the MAP sensor does not indicate the correct barometric pressure, refer to DTC P0106, P0107, or P0108 .

- With the engine idling, observe the mass air flow (MAF) sensor parameter. The MAF sensor parameter should be within 3-10 g/s at idle.

⇒ If the MAF sensor parameter is not within 3-10 g/s at idle, refer to DTC P0101 or P1101 or DTC P0102 or P0103 .

- Vacuum hoses for splits, kinks, and proper connections

- Sufficient fuel in the tank

- Low fuel pressure

- Fuel contamination

- Properly functioning fuel injectors

- Missing, loose, or leaking exhaust components from the HO2S forward

- Vacuum leaks at the intake manifold, the throttle body, the brake booster hose, and the injector O-rings

- The air induction system and the air intake ducts for leaks or for a missing air filter element

- Evaporative canister purge lines plugged or obstructed

- The crankcase ventilation system for leaks

- The HO2S for proper installation and for electrical wires or connectors that may have contacted the exhaust system

- The HO2S signal circuit open, shorted to ground, or shorted to the low reference circuit

- The HO2S sensor 1 low signal circuit for an open circuit or high resistance

- Malfunctioning engine components

-------------------------------------------------------
Here's more info:
http://www.aa1car.com/library/problem_hesitation.htm
 

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Removed the MAF sensor from the car for inspection. It did not appear to be dusty or dirty, but I sprayed it down good through both ways with CRC MAF Sensor Cleaner and let dry for 5 min. Installed back in the car along with new air filter (old filter one was not really bad yet, but put a new one in anyway). Test drove for 1/2 hour and I could not get the TC-Off light to come on during acceleration (it seems to be fixed). Also appears to idle a little better and have a little more snap from idle. Admittedly - all of this could just be wishful thinking. I'll know for sure in a few days, as the TC-Off light has been a daily observable problem and the weather is supposed to be exactly the same.

LMyer
Mine still appears to be fixed.

LMyer
 

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LesMyer:

Is this something that I can get at an Auto Parts store? I will sure give it a try... Though it has not been on for the past couple of days... I'm sure it will be.
It may or may not fix your particular problem (multiple things can cause this), but it's a cheap and easy thing to try (why I did it first without real diagnosis). I got lucky. Also cheap and easy is inspecting for vacuum leaks. Yes, you can get the MAF cleaner at pretty much any Auto Parts Store. Good luck.
 

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Noob here, seems like I am having a similar issue with my 06 G6 GTP that we bought last week with 78K on it. It runs like a champ 90% of the time but then I had the TC-off light flicker and had a ruff idle around town at <35mph range... Got on the freeway and at about 40mph it would no longer accelerate...pressed the pedal a little more and then it would finally catch on after 5-6sec and jump to 4k RPMs and be just fine until I would reach speed and let off the gas... Then as I would need to accelerate again to maintain speed...no acceleration when I press the gas and RPMs drop to 1k or less...So, I press on the gas and it repeats this process three times. The last time it happened (on this same trip) I must have gave it too much gas when it lost the ability to accelerate and killed the engine...Put the car in N and restarted it as I coasted, started right up and ran like a champ the whole way home. (50+ miles up and down canyons and then around town.) Can it be that intermittent? I will try the MAS cleaning and see if any codes are there (although no CEL came on only the TC-off.) Any other thoughts? Any help is appreciated!
 

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Noob here, seems like I am having a similar issue with my 06 G6 GTP that we bought last week with 78K on it. It runs like a champ 90% of the time but then I had the TC-off light flicker and had a ruff idle around town at <35mph range... Got on the freeway and at about 40mph it would no longer accelerate...pressed the pedal a little more and then it would finally catch on after 5-6sec and jump to 4k RPMs and be just fine until I would reach speed and let off the gas... Then as I would need to accelerate again to maintain speed...no acceleration when I press the gas and RPMs drop to 1k or less...So, I press on the gas and it repeats this process three times. The last time it happened (on this same trip) I must have gave it too much gas when it lost the ability to accelerate and killed the engine...Put the car in N and restarted it as I coasted, started right up and ran like a champ the whole way home. (50+ miles up and down canyons and then around town.) Can it be that intermittent? I will try the MAS cleaning and see if any codes are there (although no CEL came on only the TC-off.) Any other thoughts? Any help is appreciated!
For starters, make sure the CEL passes the bulb check at startup. It should light up along with all the other indicators. Then check for codes & come back with the exact codes if you find any.
 

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i know this thread is old but I'm new to the forum. I have a 2006 GTP and am having the exact same problem. Intermittent hesitation on acceleration with the traction control light illuminating. Intermittant lean bank 2 codes are also recorded. Checked the fuel trim and they were normal until taking off from a stop. Thats when the hesitation occurred. The short term trim would jump to almost 20 before evening back out. Replaced all fuel injectors and haven't received the code again. Still feels like it's hesitating on takeoff and still have the rough idle with the rattling sound. Replaced the MAF and checked the MAP sensor. Same issue. I also noticed occasionally when I takeoff from a stop, when I shift from first to second, the engine will rev up between shifts and I have to engage the clutch to bring it back down. Only does this between 1 and 2. Any new information on this problem would be appreciated. I'm starting to pull my hair out.
 
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