reduced engine power, etc etc 2006 denali

vdubpower · May 5, 2015

so the other day the reduced engine power stability control disabled CEL came on and the truck went into limp mode.

i turned it off and back on, the CEL was on but no more limp.

SInce then, everything is working fine, no lights or issues....

i did some searching here and it seems like there isnt one answer as to what the problem is....TPS or other stuff?

Can the dealer still pull a code if there is No CEL on??

obviously i dont want this to happen when my family is driving as a safety concern but i dont want to keep trying differnt fixes that dont fix it and cost me

its a 2006 denali 100000 miles

Black4x4Z71 · May 6, 2015

This is exactly what happened to my 2011' 5.3 liter Silverado while driving 70 mph on my way to work. The dealer informed that the problem was caused by a defective throttle position sensor. It was covered by a factory recall covered repair. Check with your GMC dealer to see if your truck is covered under this recall too.

vdubpower · May 6, 2015

anyone have the recall letter or bulletins on it, or is there a site to find this info?

gmtech4 · May 6, 2015

anyone have the recall letter or bulletins on it, or is there a site to find this info?

Just see a dealer , new throttle body and a reprogram IF YOUR TRUCK IS INCLUDED IN THE campaign

vdubpower · May 6, 2015

yeah i hope it is...i guess

GMCustomerService · May 7, 2015

so the other day the reduced engine power stability control disabled CEL came on and the truck went into limp mode.

i turned it off and back on, the CEL was on but no more limp.

SInce then, everything is working fine, no lights or issues....

i did some searching here and it seems like there isnt one answer as to what the problem is....TPS or other stuff?

Can the dealer still pull a code if there is No CEL on??

obviously i dont want this to happen when my family is driving as a safety concern but i dont want to keep trying differnt fixes that dont fix it and cost me

its a 2006 denali 100000 miles

Hi Vdubpower,

We can also check to see if your vehicle is associated to the mentioned recall. Just send us a private message along with your VIN.

Patsy G

GM Customer Care

vdubpower · May 14, 2015

OK so the issue occured again....about now a week after the first time

the gm rep said my truck is not involved in the recall.

i actually took it in to the dealer the other day for a oil change and the CEL wasnt, and i was short on time but I mentioned to the service rep the issue. He said it could be a number of things, the throttle possition sensor, the throttle body or even the accelerator possition sensor...costing minimum 600-800 bucks

heres my issue, ive read so many post on here that people have changed various parts but still have this problem as it seems that the problem cannot be issolated.

I dont have time/money to just waste

when we turn the car off the cel goes off and then i assume no codes can be read?? or are codes kept in memory? dontknow what to do

gmtech4 · May 14, 2015

OK so the issue occured again....about now a week after the first time

the gm rep said my truck is not involved in the recall.

i actually took it in to the dealer the other day for a oil change and the CEL wasnt, and i was short on time but I mentioned to the service rep the issue. He said it could be a number of things, the throttle possition sensor, the throttle body or even the accelerator possition sensor...costing minimum 600-800 bucks

heres my issue, ive read so many post on here that people have changed various parts but still have this problem as it seems that the problem cannot be issolated.

I dont have time/money to just waste

when we turn the car off the cel goes off and then i assume no codes can be read?? or are codes kept in memory? dontknow what to do

You're panicking ..

You have no idea what's going on

Don't get caught up in the guessing game as previous poor bastards

vdubpower · May 14, 2015

panicking..not yet...concerned yes....wife and kids are the main passengers so i dont need it going into limp mode on the freeway when she is driving..

what should i do, just take it to the dealer and let them at it?? that doesnt seem to be the remedy with other members.

id appreciate your advice, thanks

vdubpower · May 16, 2015

anyone have any other advice on this issue?

n5xl · May 16, 2015

You have three options. Take it to the dealer, take it to an independent shop or fix it yourself.

The dealer will absolutely have the necessary tools and experience to do the repair and is usually the best route to go if you are unsure of your abilities to repair something like this or simply dont want to deal with it yourself.

An independent shop will also likely have the necessary tools and experience to do the repair, however the onus is on you to choose the correct shop as not all independent shops are of the same quality and as a result, the quality of repair work can vary. If you have a good shop with a good reputation close to you, they can get the job done.

If you are not covered under warranty or if you would like to do the repair yourself, you absolutely must have an OBDII scanner to read the codes that are stored so you will know where to look first. You must also be confident in your abilities to perform basic mechanical procedures without causing damage to other components, and I would also strongly suggest obtaining a factory service manual or having a subscription to it via alldatadiy.com

I can tell you what I did to fix the problem, but you must absolutely understand that there is no guarantee that you have the exact same problem (even if you have the same symptoms) or that following what I did will fix your problem. You must look at the specific codes that will be stored in your computer controller first to know what to do next. And yes, it is possible to have codes stored and not have a check engine light.

1, Problem first occurred as you describe (driving to work one early morning, 70mph) with driver information messages as you have. I had additional symptoms on my vehicle...the throttle body was making a grinding noise sitting at idle at a traffic light. It also made a grinding noise with a key on / engine off situation, and I had intermittent fluctuating idle / poor idle quality when the engine was running. The poor idle quality corresponded to the time the throttle actuator was making a grinding noise.

2. I pulled the codes with my OBDII scanner. The scanner gave me a handful of codes to consider, one being P2135: Throttle Position (TP) Sensor 1-2 Correlation. I had other codes for overall lean conditions on bank 1 and 2. Since the throttle position sensor can absolutely affect overall fueling, I focused on dealing with the 2135 code first.

3. With the engine running and scantool hooked up, I looked at the live data and I could see that the throttle position sensor value did not agree with the accelerator pedal position sensor commanded value. While I do not remember the exact values, the accelerator pedal assembly was commanding something like a 15% opening and the TPS was reporting roughly 4 to 5% opening and that number was erratic. Again, not the exact values but you get the idea.

4. I researched the correct part numbers I needed and ordered the throttle body/throttle actuator/tps assembly and a throttle body intake gasket …cost roughly 130.00 for the TB and 15.00 for the gasket.

5. I followed the recommended repair procedure as outlined in the factory service manual. (via subscription to ALLDATADIY.COM)

6. After replacing the TB, I monitored the livestream data with my scanner and verified that the commanded value for throttle position from the pedal assembly matched the value being reported by the throttle position sensor.

7. I used the OBDII scanner throughout the following week to verify that the TPS code was cleared and did not show as pending and that the lean bank 1 and 2 error codes were not pending.

I spent roughly 150 in parts and about 15 minutes of actual repair work time to fix the problem. it could have been a myriad of other things causing my problems so that why you need your specific codes from your vehicle to know what to do. There were a few places where someone with no experience could make a mistake during the repair (chasing the lean bank1 and 2 codes first, not replacing the TB gasket, overtightening the throttle body and damaging the intake, not verifying the actual problem to begin with, etc, you get the idea.

Not sure what else can be said at this point, other than get the thing fixed via one of the three routes before it happens when your wife is driving and it leaves her stranded.