Round101

MIL came on at 497 while on road trip. Cruise control also doesn't work. Also, had temporary problem shifting into reverse. Should we turn around?

RonC7

Push the OnStar button. They can read the trouble codes and give you some advice.

Good Luck!

Ron

Round101

Well we made it... Here was the original chain of events...

1) Cruise control stopped working
2) Noticed orange malfunction indicator come on
3) stopped at a gas station to try to figure it out. After several ignition cycles, MIL still lit solid. 4) Finally decided to blaze ahead, but could not get shifted into reverse to back out!

At this point I am thinking WTF is going on this car only had 500 miles!

I pushed the car out of the parking spot and slowly started off in 1st. After 40 feet I stopped and voila - I could shift into reverse no problem.

I drove on for 3 hours with the MIL still lit solid and cruise control dead. I'm thinking maybe blown fuse?

Stopped for gas once I hit half tank. Was hoping that some different gas blended in might clear the MIL. After pumping, hit ignition and MIL still lit.

After getting back on freeway, voila - cruise control works! MIL still lit solid.

Arrive at our destination and stop for dinner, which took about 1 hour. Start up after dinner and voila - no MIL!

I find it very strange that I had all 3 of these problems hit at once and then they all cleared at separate times.

Any hypotheses on root cause? I don't want to live in continuous fear of these things recurring so want to get to the bottom of it.

Vetteman Jack

I would get it checked out as soon as possible. A dealer should be able to pull codes and tell you whether it needs to be fixed right away or if you can wait until you get home.

Round101

After sitting overnight the MIL was clear this morning, although I have a new question. The pre-500 mile yellow and red lines on the tach came back? Not sure why this is.

Back to the old problem... I called OnStar and they could not see any codes. I researched the forums further and found that there is a code P0833 that is due to some switches in the clutch malfunctioning that will trigger the MIL and also result in cruise control not working. I may need to get that adjusted. I will take it to the dealer when I get home but it seems that it shouldn't be a big risk to drive it back home.

owc6

Did the yellow line go away after engine warm-up? If it did, that's normal. It always shows up when the car is cold.

Kenafin

Was the car warmed up? Even after 500 miles if the car is cold the lines will be back lower. As the car warms up the lines start decreasing until the car is warm and the lines are back up to 6500 rpm.

Round101

It was not warm, after it warmed up the lines did go back to normal. I guess I am paranoid now that everything is a problem vs just my limited knowledge (as in this case)!

iclick

Do you have an A8 or M7? My A8 has balked going into reverse four times since new (now five months old) but only once in the past two months. When I say "balked" I mean when I shift into "R" the gear won't engage immediately, but will when shifted to "D" and then back to "R". While doing this the "R" on the DIC blinks. No codes.

Round101

I have an M7

WelderGuy

There are two switches associated with the clutch pedal. One keeps the engine from being started if the pedal isn't all the way down. The other disengages the CC if you start depressing the pedal.

Round101

(Edit: Problem not solved, keep reading)

UPDATE: Problem solved after I had a recurrence and got the code from Onstar. A search here found a thread from RandomTask. Went to dealer and had them do the software update, no problems since.

Here is the original thread: https://www.corvetteforum.com/forums...ode-again.html

#PI1439A: Malfunction Indicator Lamp (MIL) Illuminated, DTC P0503 Only Set with No Other Symptoms.

Models: 2015 Chevrolet Corvette
Equipped with Manual Transmission (MEK or MEL)
Built Prior to VIN BReakpoint F5606174

Recommendation/Instructions:
Important: Do NOT replace the vehicle speed sensor for the issue.

If following the diagnostic instructions for this code above in Service Information (SI) does not lead to a root cause, update the Engine Control Module (ECM) software.

An revised software calibration has been released to address this condition.

Update the Engine Control Module (ECM) using the Service Programming System (SPS) with the latest calibrations available on TIS2WEB. Refer to the K20 Engine Congrol Module: Programming and Setup in SI.

Warranty Information
For vehicles repaired under the Powertrain coverage, use the following labor operation. Reference the Applicable Warranties section of Investigate Vehicle History (IVH) for coverage information.
Labor Operation: 2810075 ----- Description: Engine Control Module Reprogramming with SPS ----- Labor time: Use Published Labor Operation Time.

Nice Ride

Sounds like the days are long gone when you could pull under a shade tree and a good ol boy mechanic could pop the hood with a flat head screw driver in hand and get you going again.

tunaman

We had a similar issue with the wife's '14 (A6) after taking Museum delivery. The first day we left Nashville and headed towards Charlotte to visit friends before heading back across country, and several hours into the trip I received the error code. I stopped at a gas station, tried cycling the engine several times, then called OnStar. There was a code, it it wasn't significant so we drove on.

A couple of hours later the warning was still there and it was getting late, so we stopped for food and lodging.

In the morning the issue had cleared and we were on our way. Her car now has over 20k miles without another hiccup.

Round101

I am glad you haven't had a recurrence.

I posted my prior message too soon. I just had another MIL light up this afternoon when taking my brother on a ride. Reverse was locked out this time (again). Don't know if it's the same one and didn't have time to call OnStar. Probably will be clear next time I start up but I'll be on pins & needles now every time I drive it (again). Sigh.

Round101

UPDATE: MIL has remained on for the last 2 weeks+, through a 250 mile roadtrip and 10+ engine cycles. Reverse was locked out initially, but that resolved after a short drive. Cruise control works intermittently however the MIL has remained lit.

Took it to dealer today, next step is to replace the speed sensor, which of course was not in stock and he could not give me a time frame on when they'd get it in. Once it comes in I'll get to make another 30 minute trip (each way) to the dealer and wait another few hours for an install.

This better fix it - I'm frustrated that I've had to take the car back twice now in 2 months with a third trip on the horizon.

tunaman

That sucks, but it will all be worth it once they get it rectified. Thanks for the update, and sorry it didn't just go away!

Round101

The part is finally in but the service advisor is saying it will take two days to get the replacement done. That means two trips vs just waiting which I'd rather not do. Should a speed sensor take more than an hour or two?

JerryU

Those days were gone 20+ years ago Rip Van Winkle!
That’s why my 8.2 liter ProStreet Rod has an 850 Holley Carb! Can fix a lot of things with plyers and a screw driver. But it still has a few micros’ like the electric door/window remote. Occasionally have to push the hidden emergency override button to open a door until it resets itself!

Round101

Got the car back last Friday after the new speed sensor install, and after a few spirited drives the past week, NO issues with the MIL coming on! I'm not going to declare it totally resolved yet but I'm cautiously optimistic at this point.

Thanks everyone for the advice (and moral support)!