Sayfoo

Base model '08, totally stock.
I've had the rear end jacked up for almost 2 weeks while I had a rear wheel rechromed. I put the wheel on this morning and when I started the car, I get 2 warnings on the DIC.
Reduced engine power
Service traction system
Both icons are lit up on the dash.
There are no codes stored per my $50 code reader and the battery tests at 12.8 volts. Charging at 14v plus.
I disconnected the battery and let it sit for a few minutes. The car then started and drove as normal. But, within 1/4 mile the DIC warnings and the dash icons returned and the car went into limp mode. I tried this twice.
Any ideas?

Sayfoo

No ideas???

KB9GKC

Hello,

Did you reprogram your TPMS sensor for your tires?

If you have not done this, that's your problem.

Douglas in Green Bay

torquetube

A $50 reader won't show ABS codes, so I'm not surprised nothing showed up.

The battery could be weak. 12.8V under no load doesn't mean it's charged. A brief excursion below 12V can make the warnings light up like a Christmas tree.

If the car can't see the pressure sender the TPMS warning lamp should be illuminated.

Sayfoo

The DIC does show 30 lbs pressure in the tire that I had off, so, I'm assuming that it is working. Right?
I unplugged and plugged in the electrical connector at both wheels. The connectors were clean.
I disconnected the battery and the icons return.

So, I'm getting 2 messages--reduced engine power, and, service traction system. Is this 2 different problems are are they related? Do I get reduced engine power because there is a problem with the traction system or abs?
It seems so weird that I only got this problem after the rear end of the car was jacked up 8" for 2 weeks.

Dano523

What are you rim and tire sizes (need front and back)?

Sayfoo

Totally stock. The only thing different is that I jacked up the rear of the car, took off 1 wheel, had it rechromed, and reinstalled it about 2wks later. Same rim and tire.

Sayfoo

Well, it begins. I took the car in to the dealer and for $104 they diagnosed a bad throttle sensor. They replaced the whole pedal assembly for about $400. I also asked them to flush the brake system as the car is 7yrs old. So I call back this afternoon and they told me that they THOUGHT that they had fixed the car, but after a test drive to make sure that the brakes work correctly, the original codes came back. So, now they are going to "cut me a break" and only charge me $200 more to run new wires from the pedal to the throttle body because "it's a common problem that the wires are bad".
Well, if it's a common problem, why didn't they check this first?

Could this be related to the steering column wiring harness problems that I've read about?
So, like I said, the games have begun.
It is truly amazing that this problem has been misdiagnosed for 6-7 yrs and they still cannot get it right.

truckplay

if you did not have those problems before it is most likely a weak battery. the pedal position sensors, used to fail on early C6. the pedal assembly is held on by 3 nuts and takes 15 minutes to swap. i have had folks swap out the EBCM only to have the codes return because the battery was weak. loose abs sensors or corrosion in the connectors can also cause these problems, i would try a wiggle test on their connectors

timd38

Low state of charge in the battery make the cars do goofy thing. I would start with making sure it is fully charged using a battery charger, not the car.

If it doesn't work, it didn't cost you any money.

Sayfoo

The car is at the dealers now, so it would be hard to check the battery. I did get 12.8v at the battery and the car charges at 13.5-14.2 volts. I checked the grounds and they all seemed clean and tight. Would a bad/low battery throw a code?
I couldn't get any codes with my code reader or I would have checked the pedal assembly.
I'm not adverse to the dealer charging a little more for repairs, IF they know what they are doing. But, I'm starting to get a bad feeling.

KY_C5

Im having the same exact issue on my C5. I just had a TMS motor put in, car drove perfect for 4 days, now doing exact same thing as OP has. Giving me a P1514 Code P0102, P0104. Car drives ok for 3 or 4 miles then goes back into limp mode and dies. What should I do first?

torquetube

Confirm that the connector at the mass air flow sensor is plugged in securely.

Sayfoo

As my car is still at the dealers I cannot confirm what the actual problem or cure is/will be. But, per what they are telling me, it appears that the problem is that somehow the signal from the gas pedal doesn't reach the throttle body. Bad wiring is now the culprit.
So, check all the electrical connectors between the 2 (I unplugged/plugged them in and verified that they were clean). The gas pedal sensor has been replaced on many c6's--weather actually bad or just the first step in replacing numerous parts. The actual wires have been replaced/bypassed to restore continuity. There are threads here that have this as a cure. This should be easy for your mechanic to check before replacing the gas pedal. Unfortunately, my dealer didn't do this. They just assumed that if a signal wasn't getting to the tb that the sending unit was bad.
Evidently, even with all the electronic diagnosis avail on these cars (trouble codes), they sometimes just have a general idea of what system is bad and then just start replacing parts, rather then actually spending the time to actually check the parts before replacing.

Richard A. Snitzer

to the Reduced Engine Power issue?

cclive

While it could be that this problem just happened to come up when you had the rear wheel off the car, it would be quite a coincidence. My money is on the wheel speed sensor at the wheel that you took off.

Sayfoo

The dealer called yesterday and said that the car was repaired and test driven.
It APPEARS that the problem was the wiring between the gas pedal and the engine. I've seen this repair on this forum. They supposedly installed bypass wiring to fix this problem.
Yes, weird coincidence that it happened when the car was jacked up for 2 wks.

Sayfoo

I've got the car back and it appears to be repaired.
BUT--this brings up another question.
The 1st mechanic's assessment was possible bad throttle sensor and/or wiring from the throttle sensor to a computer. The mechanic didn't or couldn't check to see which was bad (even though the service writer told me that the wiring was a common problem on various chevy models). He replaced the pedal sensor assembly for about $400, which may of may not have been bad. Only after a test drive after they bled/replaced the brake fluid and the warning lights came back on did they work on the wiring.
The dealer says that the wires shorted out and burned out the pedal sensor. I'm thinking that it is more likely that there was a open circuit in the wiring and the signal just wasn't coming through and the pedal sensor was/may be ok.
I guess I'll never know, but I don't totally trust the dealer.

schpenxel

I think you're probably right. They'll never admit a mistake.

RICH 28

Funny how the second sensor didn't short out because of the bad wires. If only you could put the old sensor back in to see if it works and get your money back.