Red C6 Z06

Strange for me anyway...

I was driving between client sites and I had shut the car off for just a couple minutes to go into a building to turn in a visitor's pass. When I came back and started the car it faltered and jerked and displayed "Reduced Power Mode" (or whatever those correct words are) and the check engine light was on. I shut it down immediately and started it again after about 30 seconds. It started the same way and I got concerned. I knew that I couldn't get it towed from where I was (another unnecessarily long story), so I figured I would drive it a ways to see if it improved or at least get it closer to home to have it towed.

I drove it slowly about a mile and the condition continued with no improvement. I was thinking about broken lifters, etc., and was just about resigned to imagine that it was going to be a big deal. I needed to stop for another few minutes (half thinking it was not going to start the next time). When I restarted it after about 3 minutes the car started and ran just fine! The check engine light was still on, but that didn't surprise me (stored codes). I was pessimistic that the condition would return soon, but in another 2 hours of driving there were no adverse effects (although the CEL stayed on).

When I got home I needed to get gas and that took me another few minutes. When I restarted the engine after getting gas, the check engine light was OFF as if nothing had happened!!!

I have been thinking about this situation overnight and have concluded that the condition must have been electrical/electronic since the engine ran fine once it recovered. I didn't push it however and am still concerned that it might be an indication of things yet to come. Before the initial "failure" I had been driving very slowly over some very rough roads (full of potholes) that I couldn't void, and it occurred to me abnormal vibrations could have shaken electrical connections - although what could have reseated those connections is beyond me.

Anyone ever experience anything like this?

JDMUSCLE

Hate these type of situations.... Very hard to diagnose since there is not a set pattern to recreate!! Have one of these headaches myself.... Very frustrated.

I'm sure that this message will be documented in the owners manual along with a description. Check it out and maybe visit your local dealer, maybe they have experienced this with other cars as well.

Mjolitor 68

I've seen it too. Maybe some kind of computer glitch. Nothing serious ever occured though

QwikC

Experienced identical symptom, problem was resolved by replacing the "throttle actuator" as it proved to be the cause. G/L.


A few suggestions . . .

1. Check for -- engine related, blown fuses.

2. Disconnect & reconnect the cable to the throttle body.

3. Physically inspect the inside of the throttle body to see whether there's any interference and there’s freedom of movement of the actuator.

4. Dependent on the condition of your filter and environment, replace the intake air filter -- this should be replaced more often than recommended in the owners manual, imo.

5. Finally, IF you’ve modified your car, or re-tuned the PCM, it may be a good idea to return it to stock specifications and see if this resolves the problem.


Reference: http://forums.corvetteforum.com/c5-t...-p2101-hc.html

urslooow

how about getting a code reader and lookin up the codes for the dx

Halltech

Did you purchase your car new or used?

This is a typical issue with ported throttle bodies, where the tuning was done incorrectly. The MAF and MAP must see eye to eye, and if there are any electrical anomalies with the throttle position sensor and MAF sensor, Limp Mode can result. Usually, you can walk away from your car for 5 minutes or so and then try starting your car, and it usually starts right up.

I would definitely make a trip to the dealer, and have them look into the code that was tripped. I could be a bad throttle position sensor.

My recommendation to everyone that purchases a used Z06 is to have the dealer reflash the ECM with the most current stock calibration, to assure that the ECM is stock. Otherwise, if your ECM has a tune, even if you are not aware of it, you could lose your drivetrain warranty.

Jim Hall

z06clif

I had a similar situation. Brought it to the dealership and it turned out to be a low battery.also they reflashed the computer with a" battery drain update". I put it on the tender and havent had a problem since.these cars get "whacky" when the battery gets low. Strange things happen

Clif

chasboland

Same thing with me when my battery went dead. It just took about 30mins for the computer to reset. The service engine light went away after a day or two after 10 or so cycles.

40YRW8

I had this happen to me 3 times in the first year I owned the car. Each time was near my house and I "Limp Moded" it home. The third time, I took it to the dealer to have the code read and it had a code that listed some sort of Throttle Position sensor not read message. Each time it cured itself after being shut off for several minutes. The dealer found all throttle sensors working and cleared the code. That was the last time it happened and that was about 2 1/2 years ago. It was also before I had anything done to the car mod-wise. Sorry, I don't remember the code itself. I put it off to be some sort of auto-epilepsy
Gary

Red C6 Z06

Thanks guys.
I have a code reader, but for a few months now it has been misplaced and I couldn't find it. Well as it turns out I discovered it last night, so I will use it to check codes. From what you guys have said however I'll bet is has something to do with the throttle body, since the battery hasn't been a problem and it is the first time it has happened to me in 17,000 miles (it had 3k on it when I bought it new). As you may recall in my OP, I mentioned a rough road and I suspected that it could be a connector, well I still do, and now especially.

Thanks again all, I'll post an update after I get the codes.

Red C6 Z06

OK Guys, as I suspected, code P2176 ("Minimum Throttle Position Not Learned"). I will check connectors (and if suspicious, will inspect and clean internally) and let you know if I find anything else.

Thanks for all your help.

morris

Had this happen to me two weeks ago except the code stayed and it was related to Cat efficiency.

The Dealer had ordered new cats to install but then recived a cancellation saying that there was a new softwrae update. they installed it and so far I have not had any addtiopnal issues.

Red C6 Z06

Glad to hear software fixed it for ya (tough decision - new cats or software patch - no lo contendre )