Do I need a new throttle body?

Flywatersmalli

Original poster
Member
Nov 27, 2012
11
Hello, I had originally posted this on that other site but was referred here. Great site guys! Seems a whole lot more active as well. Anyway, here goes.....

End of August or so, I got a CEL, error code P0122 (TPS). Going by the wealth of information here on the forums, I gave it a cleaning and reset the error code. Some time goes by and the CEL comes back, same code. So I pull it apart, clean it again and all is fine. Fast forward to this last saturday, backing out of the driveway and I get the dreaded reduced engine power and stabilitrak disabled lights. I turned it off, a minute later it started right up but the CEL is back, same code again and that has happened 3 or 4 times in the last 2 days. Gave the wires going in the wiggle test, all seems to be ok there.

Now when I cleaned the throttle body, I did not remove it, I got in there pretty good though. Is there anything else I can try or do I need a new throttle body? Any input would be greatly appreciated!

vehicle info if needed: 2006 Trailblazer LT EXT 5.3L Thanks!
 

The_Roadie

Lifetime VIP Donor
Member
Nov 19, 2011
9,957
Portland, OR
If it's not flexed or damaged wiring, I'd guess it's the sensors inside the TB. Got a buddy to swap with, or a scan tool to look at the sensor data?

Welcome to the site we all created AFTER the new owners of trailvoy annoyed us enough to run away and take the ball with us. They may own the posts and the archives, but WE have the community spirit and almost all the experience.
 

Flywatersmalli

Original poster
Member
Nov 27, 2012
11
the roadie said:
If it's not flexed or damaged wiring, I'd guess it's the sensors inside the TB. Got a buddy to swap with, or a scan tool to look at the sensor data?

Welcome to the site we all created AFTER the new owners of trailvoy annoyed us enough to run away and take the ball with us. They may own the posts and the archives, but WE have the community spirit and almost all the experience.

Its not the wiring, at least as far as I can tell. Everything seems to be tight and at least the reference wire is pushing a stable voltage even when I wiggle it all around. I tried that tonight. Nobody to swap one with and the only scan tool I have access to is one of the cheap OBDII readers. It gave me a starting point and thats about as far as that will go. I found a throttle body new for $130. I may just do that and hope I have it pinpointed enough. Hate to spend $80 or whatever to find out what it is then have to buy the part anyway. I think I have it narrowed down to the sensor itself.

Thank you for the warm welcome! What a great site!
 

BRomanJr

Member
Dec 9, 2011
371
Flywatersmalli said:
Hello, I had originally posted this on that other site but was referred here. Great site guys! Seems a whole lot more active as well. Anyway, here goes.....

End of August or so, I got a CEL, error code P0122 (TPS). Going by the wealth of information here on the forums, I gave it a cleaning and reset the error code. Some time goes by and the CEL comes back, same code. So I pull it apart, clean it again and all is fine. Fast forward to this last saturday, backing out of the driveway and I get the dreaded reduced engine power and stabilitrak disabled lights. I turned it off, a minute later it started right up but the CEL is back, same code again and that has happened 3 or 4 times in the last 2 days. Gave the wires going in the wiggle test, all seems to be ok there.

Now when I cleaned the throttle body, I did not remove it, I got in there pretty good though. Is there anything else I can try or do I need a new throttle body? Any input would be greatly appreciated!

vehicle info if needed: 2006 Trailblazer LT EXT 5.3L Thanks!

I had a similar problem with my 5.3, it would go into REP mode first occasionally and then became daily and finally multiple times a day. I did clean the TB, it was not very dirty (the 5.3 doesn't have the PCV problem of the I6), then checked the wiring like you did.

What I found from my 2004 schematics is that there is a separate TAC Module for the 5.3 located between the left fender and the brake Booster on the firewall. You have the newer 5.3 with DOD (AFM) so it may be different. I removed the connectors, cleaned with air, plugged them on and off a few times then applied dielectric grease and reconnected. At this point is has been over 6 months with no events.

Not sure you are having the exact same problem but hope this helps track down your issue.
 

Flywatersmalli

Original poster
Member
Nov 27, 2012
11
Thats worth a look! I dont know if it is laid out the same or not but one way to find out. Its just so weird. The wiring for the TB goes right into the computer and everything points to the TPS being bad. I'll check it out this morning yet. Worth a shot....

By the way, I am getting another code. P2135, I don't remember the exact wording but its something along the lines of sensor 1 and 2 dont jive. That help pinpoint it for anyone?
 

Mooseman

Moderator
Dec 4, 2011
25,344
Ottawa, ON
Searched for P2135 and found this on another forum: P2135 help!! - ChevyTalk --The Social Network for Chevy Fans

I need some major help. I have a 2006 GMC 3500, CC/LB, 6.0 gasser, this is my service truck. Its tossing a P2135 code at random, I replaced the throttle body and checked the connection there, they both looked good. Still throws the code with the new TB, did a little research about some grounds on the back of the heads, and certain fuses maybe being weak and causing it, but I'm way too busy to tear the truck apart so I'll carry my code reader with me but any help would be much appreciated. Thanks

There was a serice bulitian about a broken cable on models up to 2004. It may be the same area. Is there an area where the harness to the throttle position sensor may flex excessively from engine movement?

Quote:



SES Light and Reduced Engine Power with a DTC P1516: DTCs P0120 , P0220 , P1514 , P1515 , P1518 and P2135 May Be Present; 04 Trucks and Utilities with GENIII V-8 Engines - kw 4.8 5.3 6.0 #PIP3089 - (Jul 30, 2004)

SES Light and Reduced Engine Power with a DTC P1516: DTCs P0120, P0220, P1514, P1515, P1518 and P2135 May Also Be Present
.

The following diagnosis might be helpful if the vehicle exhibits the symptom described in the PI.

Condition/Concern:
SES light and reduced engine power with a DTC P1516. DTCS P0120, P0220, P1514, P1515, P1518 and P2135 may also be present.


Recommendation/Instructio ns:
If the SI diagnostics do not isolate the cause, inspect the Yellow TAC Motor Control Circuit (581) about 1 inch to 4 inches from the throttle body connector to see if it is broken inside of the insulation. Repair as necessary.

Models:
(03 - 04 Cadillac Escalade C1, C6, K1, K6) and (03 - 04 Chevrolet Avalanche C1, K1, C2, K2) and (03 - 04 Chevrolet Silverado Truck C1, K1, C2, K2, C3, K3 ) and (03 - 04 Chevrolet Tahoe C1, K1 ) and (03 - 04 Chevrolet Suburban C1, K1, C2, K2, C3, K3 ) and (03 - 04 GMC Sierra Truck C1, K1, C2, K2, C3, K3 ) and (03 - 04 GMC Yukon C1, K1 ) and (03 - 04 GMC Yukon XLC1, K1, C2, K2, C3, K3) and (03 - 04 Hummer H2 N2 ) and (03 - 04 Buick Rainier S1, T1 ) and (03 - 04 Chevrolet Trail Blazer EXT S1, T1 ) and (03 - 04 GMC Envoy XL XUV S1, T1)
 

Flywatersmalli

Original poster
Member
Nov 27, 2012
11
Update....

I went over that wiring with a fine tooth comb, so to speak, everything there seems to be in order. Pulled the plug from the TB, blew it out with air, coated the pins with dielectric grease, reset the codes and put everything back together. I let the engine idle for awhile and tried to recreate whats going on. Wiggling wires, smacking stuff that I shouldnt be and so on. Nothing. Then, I took it for a drive, made it a block or so and the CEL is back. Back to the one code P0122. So... I got home and called a guy I know that works at a shop, said I did everything he would have short of running a scope (which I dont have and he doesnt have the authority to "just let me use") and he figures its the TPS too. Well, I found a used TB assembly locally off of a totaled 2008 Silverado for $90. Guy will let me return it if that doesnt fix my problem. Thats service! So, I am going to pick it up and install it tomorrow after work. Will follow up as soon as I get it in and check it out.

Mooseman,
There is just the one bundle of wires that goes from the TB to the brain box, nothing that moves much at all. I appreciate the idea though! I ran right out to check.
 

Mooseman

Moderator
Dec 4, 2011
25,344
Ottawa, ON
Recommend that while you are replacing the TB to disconnect the battery for 30 minutes to reset the PCM. We usually do this while cleaning the TB. Might be a good idea so it resets itself to the new TB and TPS.
 

Flywatersmalli

Original poster
Member
Nov 27, 2012
11
Mooseman said:
Recommend that while you are replacing the TB to disconnect the battery for 30 minutes to reset the PCM. We usually do this while cleaning the TB. Might be a good idea so it resets itself to the new TB and TPS.

I planned on doing that. Do I need to disconnect the battery completely or just the neg cable to reset the PCM?
 

Flywatersmalli

Original poster
Member
Nov 27, 2012
11
Well, new throttle body is in. I put it in, and hooked everything back up and then I started wiggling things around trying to recreate my problems. Drove around for the better part of an hour, nothing. The telling sign will be running it cold in the morning but from what I can tell so far, I am going to say that I had a faulty TPS. The new one seemed to be a bit smoother than the one I replaced when I moved the blade as well. Motor was going perhaps? At any rate, it seems to be good to go. When I start her up in the morning when its 15° I'll know for sure and will report back. Thank you all for your help!
 

Flywatersmalli

Original poster
Member
Nov 27, 2012
11
After driving in to work today on a cold engine, no trouble codes, no issues. Runs like new! I am going to say that my issue is now resolved. :thumbsup: Thank you guys for your help!
 

CaptainXL

Member
Dec 4, 2011
2,445
Flywatersmalli said:
The new one seemed to be a bit smoother than the one I replaced when I moved the blade as well. Motor was going perhaps?

More than likely! I suspect you might have unknowingly nuked your old TB. Never move the throttle valve manually by hand unless it is removed from the vehicle. I repeat NEVER. It can damage the Throttle body. DOn't do that. Especially if the key is on. Disconnect the battery before beginning any electrical work.
 

Flywatersmalli

Original poster
Member
Nov 27, 2012
11
CaptainXL said:
More than likely! I suspect you might have unknowingly nuked your old TB. Never move the throttle valve manually by hand unless it is removed from the vehicle. I repeat NEVER. It can damage the Throttle body. DOn't do that. Especially if the key is on. Disconnect the battery before beginning any electrical work.

Actually when I did that Captain, both units were out of the vehicle and sitting side by side on the work bench. The old one seemed as a gear was slipping. Perhaps that was my issue all along, either the motor itself or the gear inside the TPS housing. At any rate, problem is fixed and can be attributed to the throttle body unit itself. Hopefully this series of posts helps someone else in the future!
 

GS_Geoff

Member
Jul 7, 2012
21
Just saw this thread. I had the same symptoms, brand new throttlebody for $130 fixed my problem as well.
 

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