I've started to get this code so much i can't stand to drive my car anymore cause its a PITA constantly going into reduced power mode.
Ive tried to figure out at what point it throws it but I've come to the conclusion it doesn't matter what I'm doing its just random. it will throw it during normal acceleration, WOT or even at stop lights when I'm not touching the throttle. I've replaced the pedal assembly with a brand new one and it threw the code within 5 miles. According to the previous owner the throttle body was replaced and it still did it. the pcm has been replaced as well. my tuner checked continuity on the wires with no luck on anything standing out. the dealership spliced on a new connector in the harness at the throttle body which didn't help either. does anyone have any clue at what my next option is? like i said i can't even enjoy my car anymore and it sucks from all the other threads I've read everyone seems to have luck with changing the TB or the pedal but I'm at a loss now…
thanks

2005 c6 z51

 

found this post, see if this helps:




There is a bulletin for that code PIP3089B. Possible bad terminal crimps and/or broken wire inside of the insulation at the TB connector. With the car running try grabbing and moving the TB connector and harness and see if you can get the code to set.




#PIP3089B: SES Light And Reduced Engine Power DTC P0120 P0220 P1516 P2135 - keywords accelerator actuator APP blade body connector connection DTC L33 L59 LH6 LR4 LM7 LS1 LS2 LQ4 LQ9 module position reduce sensor - (Oct 31, 2006)

Subject: SES Light and Reduced Engine Power DTC P0120 P0220 P1516 P2135

Models: 2004-2006 Buick Rainer
2005-2006 Cadillac CTS-V
2003-2006 Cadillac Escalade
2003-2006 Chevrolet Avalanche, Corvette, Express, Monte Carlo, Silverado, SSR, Suburban, Tahoe, Trailblazer
2003-2006 GMC Envoy, Savana, Sierra, Yukon
2003-2006 Hummer H2
2005-2006 Pontiac GTO
Equipped with a 4.8 5.3 6.0 or 7.0 V-8 Engine

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern:

A vehicle may be brought into the dealer for a reduced power message, and DTCs P0120, P0220, P1516, P2101, or P2135.

The Throttle Actuator Control (TAC) / throttle body type trouble codes, may be caused by a loose wiring crimp at the throttle body connector, or a broken throttle body circuit.
Recommendation/Instructions:

Complete the current SI diagnostics for any symptoms or trouble codes found. If a intermittent T/P or TAC module type code is occurring complete the inspections below.

1. Inspect all related throttle body terminals for a loose wiring crimp. The loose crimp may be difficult to find, and the poor connection will be between the terminal and the copper strands of the wire. Wiggle test the individual throttle body circuits to see if the concern can be duplicated.
2. Inspect the related circuits for broken wires inside the insulation. The outer wire insulation may look fine, but the internal copper strands may be partially broken. Breaks in the wires usually occur within 1 to 4 inches of the throttle body connector. Wiggle testing may also induce a trouble code to set.
3. On C/K trucks complete SI procedures for voltage drop on grounds G103 and G104. Grounds G103 or G104 may be loose or corroded.

If a terminal crimp or a broken wire has been found, repair or replace only the circuits involved. There is a throttle body pigtail connector available through GMSPO, but installing this pigtail connector may cause other intermittent TAC module/TP codes at a later date. If this pigtail must be used, please follow the SI procedures for Splicing Copper Wire Using Splice Sleeves. (the proper Kent-Moore crimping tool must be used for this repair)

__________________
David - 07 LMB A6 1LT Z51 QX1 - SOLD

www.reichertwoodstock.com/

GM VIN reports, build dates and recall info - PM me with your email addy and VIN (98 and newer only)!

GMautotech is offline Report Post

 

thanks for the info. yea I've tried setting it by wiggling wires at the tb but no luck

 

I would probably start by looking for a problem in the 5V reference at the throttle body (the light blue & black wire, according to my manual). Measure the voltage between that and the low reference (the tan & white wire) using a fast DMM with a MIN/MAX function like a Fluke 87. Set it to MIN and clear the DTC. Drive around until the DTC comes back and see if the MIN display shows a voltage drop.

If that looks okay, I'd move on to looking for a wiring problem with the other signals.

 

post #2; steps #1 and #2

If you have no test equipment, no Tech 2, but you can clear the code, clear it. Start the engine, let it warm up. Go to the small U-shaped harness exiting the Throttle Body. Wiggle it, move it around, see if you can cause the code to come back. There is one signal wire in that sharp bend that breaks under strain and is one cause of this MIL. And more so in early C6s.

If you've explored this common failure and the TB has been replaced, there is only one more component not mentioned and a longer shot, the throttle pedal sender unit.

 

its weird that it does it when its just sitting at idle as well. i can understand that it would when you accelerate and they aren't "talking" correctly, but at idle I'm not sure why it would throw that code unless it is a broken wire that looses connection from the vibration.

 

There is not much left. At this point I might be questioning the TB if you only have someone saying it have been replaced. BC one contributor to this series of MILs is the TPS which is integral to the TB (not separately replaceable to my knowledge).

Actually, there is a critical "handshake" signal - TPS to ECM (idle control circuit) that, if lost, the ECM is not going to be able to follow the idle RPM table.

 

First off I am not trying to start a fight here, but am I missing something. If you are constantly getting the code and it happens at different times, why have you not had it fixed? If you cannot do it your self I would take it to a reliable shop. Does not have to be the dealership. I am sure that if you go to your regional section and ask for a good Corvette shop in your area you will get the info you need.
Based on the replies, it sounds like you have a good starting point to try and correct teh issue.

 

been at the tuners for 2 weeks now. he's rewiring it, the dealership said they think its wiring. he tried to tune it out a month ago then i drove it for a week or 2 and replaced the throttle pedal and he tweaked the tune some more but none of that worked so now we are rewiring. so its been quite the process sorry for not mentioning that.

 

throttle body will be my next step, I'm gonna port mine myself when i get my car back not sure if it will help or hurt. I've heard the same thing you must replace the full TB and can't replace it separately

 

Somebody needs to validate the signals at the TB and zero-in on the actual problem. Swapping parts and rewiring half the car is not the way to go.

 

we have monitored the voltage signals and didn't see anything irregular. i was told is in common for the 05 to have a wire problem thats why we are now going that route since most everything has been replaced.

 

An intermittent wiring fault could be detected by logging the max potential between both ends of each circuit.

Don't get me wrong - I'm sorry for your predicament - but the fix here is to first diagnose the specific problem. Replacing everything is way too expensive and time-consuming.

 

easier said than done i guess. my tuner has spent a week logging trying to find something but couldn't get it to throw the code. thats why we decided to run new wires so far. ill update once the wiring is finished

 

just an update. after having a brand new wire harness made and ran from the throttle body to the cpm and the cpm to the throttle petal i have had no more issues! FINALLY I'm able to drive with no more reduced engine power issues!!

 

Glad you got it fixed!
Merry Christmas!

 

I have a quick question what is the CPM I just got a corvette about 3 months ago and I started having the same problem.

 

What wiring did you replace to fix this?