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Discussion Starter · #1 ·
2007 9-7X (re-badged Trailblazer), 5.3 V8 (LH6 engine; with the 4L70E); 135k miles.

Hi,
Not sure if these are related problems:

- Throttle has become sticky all of a sudden, sometimes at idle it stays around 1200 RPM's or a bit higher when it really should be way below that.
Most of the time, it is way below, around 730 RPM's.

- At every gear shift, the car JUMPS (rather strongly) between shifts, like if there were a delay and it caught up to the shift all of a sudden.
It has done this in the past occasionally, but only between 2nd and 3rd. Now it is at EVERY single shift, no matter the gear, the speed at which I am going, etc.

Just prior to the above, I had a "stabilitrak" warning light on (which also has happened in the past but very occasionally, usually followed by the engine conking out and having to wait a few minutes before restarting; then running OK.)

Also, I cleaned my Throttle Body with Carb & Throttle Body Cleaner. It was very dirty. I did do something wrong at first, which is manually opening the throttle to see how I would have access and how dirty it might be--which is NOT the way to do it. My understanding is that you should never do that (or risk having to reprogram it); instead you should turn the ignition without actually starting the car, and press on the accelarator pedal to open throttle to then clean it. Which is what I ended up doing with a friend. I don't know if this created this sticky throttle problem but I would say no, since the car ran fine for quite some time after that. Logic would seem to indicate the problem is elsewhere.

These are the DTC codes I got from an ODB phone app (not the most sophisticated diagnostics tool.)

- B2AAA

- No trouble codes set
P0000

- B Camshaft Position - Timing Over-RetardedBank 1
P0015

- Customer specific trouble code. See manual.
P01AA

- Customer specific trouble code. See manual.
P1621

From another ODB app:

- P0106
Manifold Absolute Pressure/Barometric Pressure Circuit

I've cleared the codes to see which come back and so far, after about 2 miles, both ODB apps give me P0106 code (only that one.)

Over the last 1.5-2 years, I've put $ into this car: water pump, belts, starter, both rear air bags, etc.; and I would like to fix this to get it back to "normal".

I cannot find a good shop in my area, unfortunately. The GM dealership is a complete joke; my local mom and pop shop is great for simple things, oil changes, etc.; but not for this type of issue; they basically either cannot diagnose properly or if able to diagnose, they "throw the book" at me (for example: they wanted $1,100 to replace water pump. I bought the parts myself for about $300 and had another mechanic put them in for another $300 so basically half the cost. The "other" mechanic is not good at diagnostics so I have to do that myself and then, I can buy the part needed and either DIY with a friend or bring it to the "other" mechanic to swap it.)

Would appreciate some feedback on the above, if you can.

Current situation: P0106 is back. Gear shifts on every gear is sudden/jumps. Car running rough.

Thanks.
 

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TrailblazerSS
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Go to a parts yard a pick some parts off another truck. Map sensors are all over. My truck did kinda the same thing when my MAF went bad. Can you view sensors with your scanner? Try to see which sensors are erratic.

Sent from my SM-G991U using Tapatalk
 

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Discussion Starter · #3 ·
Go to a parts yard a pick some parts off another truck. Map sensors are all over. My truck did kinda the same thing when my MAF went bad. Can you view sensors with your scanner? Try to see which sensors are erratic.
Thanks for feedback. I can't see anything erratic in what limited sensors I can track with the app.

If I clear the P0106 code, I hear some noise in the engine compartment; CEL goes off. Rescan with the app and it gives me same P0106 code, consistently (whether CEL is on or not [yet].)

I did clean the MAF sensor about 6 months ago so either it needs to be replaced, or it's something else. But I would tend to agree with you on replacing it, seeing you can confirm something similar on your side.
 

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I have an LS7 blade style MAF so it was cheap to replace

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Discussion Starter · #6 ·
Well, I've replaced the MAF sensor. And when starting up after that, I noticed a nasty hissing sound from the engine. Investigating that, I found a small rubber tube/pipe cracked so leaking, replaced that and no more loud hissing from engine.
So far, no CEL's, and car seems to run fine/smoothly. Just very early to tell though, we'll see if it stays that way over the next few days.
Hopefully, it will. Will report back here.
In the meantime, thanks to everyone whom provided feedback.
 

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Discussion Starter · #7 ·
So this is the update after about 24 hours. All was fine, no more hard shifts or throttle/idling problems.
However, today, while parking (so very low RPM's), I got a CEL and "WARNING Stabilitrak OFF" -- the car shudders and usually turns off (it's happened in the past, very infrequently.) I parked and turned off the car; 5 minutes later, it seemed back to normal but CEL is still on with this code:

P2101
Throttle Actuator A Control Motor Circuit Range Performance

I have no idea what that really is.

I did change the Throttle Pedal Assembly (inside) which has one sensor; and obviously it is not that.

I've cleared the CEL to see if it comes back.

I wonder if this indicates some module like the Powetrain Control Module, the Throttle Body itself, etc.

Any suggestions here would really help.
 

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Check the pedal assy you changed for loose wires, check the pins in the connector are not bent, I believe there are 2 sensors in the TB and 1 at the pedal which is why it's code A there's B and C I don't know which is whi h tho. Grounds, can't stress that enough, if you think they still look good, still add them. I always add atleast 4. Batt to block, block to frame, frame to body, frame to body rear.

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Discussion Starter · #9 ·
Check the pedal assy you changed for loose wires, check the pins in the connector are not bent, I believe there are 2 sensors in the TB and 1 at the pedal which is why it's code A there's B and C I don't know which is whi h tho. Grounds, can't stress that enough, if you think they still look good, still add them. I always add atleast 4. Batt to block, block to frame, frame to body, frame to body rear.
Sorry for the delay in reporting back.
The CEL/ DTC codes have not come back--in about a week, now. I will still check what you mentioned. I am not sure though what you mean by grounds. Where are those? You say "still add them," I know what a ground is or the concept but in practice, as related to this issue?

Except today, I got the "Stabilitrak" warning, car shudders and stops.
I was not driving the car so I'm waiting for the car coming back to check the DTC's.

I have had this happen ("Stabilitrak" warning and automatically being turned off) several times now and it seems to be occurring more frequently. Something is obviously wrong with this and in need of fixing.

Any ideas? Should I open a new thread for that?
 

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Add grounds as in add grounds.. make a ground strap from batt to block, block to frame, frame to body, rear frame to body.. it will help in every aspect of power distribution..

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