Hello everyone, I am new to this forum so please bear with me. Recently, my check engine light on my 2019 Stingray with only 23,334 mile came on and upon investigating as to why, my OBD2 scanner found two codes both being the same P257D. This code relates to the engine hood latch sensor and is fairly common with GM vehicles using the same latch as our Corvette's, but most common with the Silverado trucks. Basically it says that the hood is technically not closed even though mine clearly is. I am able to clear both code(s) and the check engine light will remain off even on long drives, but the moment I open my hood and close it, the check engine light comes back on after a few minutes of starting the car. It does not appear to affect performance whatsoever, (although I've read that in some vehicles, this code will limit the speed limit down to 5 MPH so's to avoid the hood from popping open while driving).

The issue now is that even though the check engine light has not returned (just as long as I do not open and close my hood), I now have a "permanent" P257D in the system. I read that there is way of clearing the code called a 15/200 method. This entails 15 warm starts and 200 miles of driving. I can then go back and clear it with the scanner.

I made a quick pit stop to my local service center and was told that they have heard of this but not common with the Corvette. I was also told that they would need to run a diagnostic system test to determine if it is indeed the sensor on the lock, but can also be the connector or the wiring leading from the computer to the sensor. The test would run me $235 which I have no problem paying, but I am afraid that they are going to come back with the worst scenario and that is that the wiring harness needs to be replaced.

With all this said, my question therefore is, has anyone else experienced this issue and should I just bite the bullet and have the dealer service center go at it?

Thank you and any advice or suggestions would be greatly appreciated.

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First off you're in the wrong Forum...your 2019 is a C7 and your in the C6 Forum...looks like you have no experience with electrical diagnostics for a very simple circuit...you DON'T need a dealership to diagnose it and I highly doubt it's a bad harness...may just be a sensor...find an auto electric shop in your area...they do this kind of work every day...a dealership tech can barely diagnose a lightbulb !!...these DTC's are stored in Mode 10...the repair must be correctly performed and then the DTC will clear after so many drive cycles.

 

Thank you C5 Diag for correcting me on my post. I will take your advice and take it to an electrical specialist rather than go back to the dealer.

 

You don't need a, auto electric shop.
The hood latch on the passenger side has a latch electrical sensor. The latch can be adjusted up just a bit so the sensor is triggered, or maybe just push down on that side a bit more.
The hood also has a round hood stop on it. First try to turn it in just a bit, so the sensor completes the contact. Not rocket science here.

AI:
A non-working C7 Corvette hood latch sensor, often showing a "Hood Ajar" message, is typically caused by a faulty, dirty, or misaligned latch sensor/microswitch, or sometimes a stretched release cable. Common fixes include lubricating the latch, cleaning the mechanism, adjusting the latch position, or replacing the sensor.

 

How did fixing the hood latch go?

 

No go on the fix. I removed the latch so that I could visually see the micro sensor switch and sprayed it with electric contact cleaner spray. Thought I had it resolved as the check engine light did not immediately come on. Turned engine off, waited a minute, turned back on and check engine light stayed on. Scanned for codes and threw the P257D code. I cleared the code for now and just ordered a new passenger side hood latch that comes with attached sensor micro switch. Hoping for the best once I install the new latch. Cheers!

 

Did pushing down on that side of the hood, shut the warning light off?

 

Yes I did. Had the wife push down on the passenger side sensor location while I monitored the dash. Ordered a new latch online and scheduled to arrive Monday at my local GM dealer. Hopefully a new latch with sensor will resolve it. Total cost is $88. Can’t imagine cost at the dealer service center. I walked away when I was quoted $235 just to open the hood.

 

Then the sensor should be working. Did you adjust the corner hood stop, in, just a bit, so the bar on the hood pushes a little farther into the latch?

 

How did the new latch work out?

 

Update on P257D hood error code. The new passenger side hood latch came in a few days ago and I just got around to installing it. Install took less than 10 minutes, start to finish. The hardest part was unplugging the sensor cable because of those GM secure tabs. Also you must transfer the rubber bump stop from the old latch to the new one as new one does not come with it. After completion, started the engine and watched for check engine light. No light after about 5 minutes of running, so I took the car for a 15 mile drive with four start stops and still no check engine light. Put scanner to it and threw no more codes. So the issue from the start was a bad latch sensor that unfortunately cannot be replaced on its own. By the way, the new OEM latch cost a mere $88 from GM online and had it direct shipped to my nearest GM Dealership at no cost.