v6 NPP fuse pull limp mode

Mr.DoubleB · 06-09-2018, 10:48 AM

I pulled the NPP fuse (F51) shortly after getting the car.
I've put about 800 kms on it since I've bought it with mostly city driving with out issue.
The first time I took it on a long highway drive was today and it went into limp mode with a CEL. I pulled over and shut the car off hoping it would just reset but it didn't. I put the fuse back in and restarted the car and it came out of limp mode but the CEL remains.

Any ideas what the problem is? Has any body experienced this before?
Should I take it to a dealer to reset the code or just unplug the battery?

2SSVERT · 06-09-2018, 11:49 AM

First thing you need to do is pull the fault code and see what's going on. Most auto parts stores will get you the code for free.

TedJS · 06-10-2018, 09:34 AM

Why are you pulling this fuse again? Putting the car in sport mode keeps the exhaust valves open all the time.

Good luck with your check engine lamp and subsequent diagnosis.

Glen e · 06-10-2018, 09:36 AM

Quote:

Originally Posted by TedJS

Why are you pulling this fuse again? Putting the car in sport mode keeps the exhaust valves open all the time.

Good luck with your check engine lamp and subsequent diagnosis.

No it doesn't. The valve still shut at interstate speed.

Mr.DoubleB · 06-10-2018, 01:19 PM

I took it to the dealership but the service department was closing and the techs had already left.

The service manager had a code reader and said it looked like some type of short in the fuel system but couldn't do anything about it until Monday.

When I restarted the car after the manager looked at it, it had come out of limp mode and on the way home the CEL disappeared.

I've been driving around the city today and it seems fine but I haven't had it back on the highway yet.

TedJS · 06-10-2018, 07:06 PM

Quote:

Originally Posted by Glen e

No it doesn't. The valve still shut at interstate speed.

Hmmmm. I don't think they do in track mode. I have driven my SS with GM scan tool hooked up. They are indeed commanded open all the time at highway speeds - just checked it for my own information on how system worked etc. I know they will close with AFM active under certain conditions but with the cylinders dropped out the tone of the exhaust is "odd" if they are left open.

At any rate, seems kind of weird to pay that sort of money for the option and pull the fuse out when it is managed properly through software.

Wierd Harold · 06-10-2018, 07:21 PM

You have a problem still. The code will still be recorded in the history side of the pcm,best to get it looked at.

Mr.DoubleB · 06-14-2018, 11:17 AM

So it turned out the high pressure fuel pump had failed and was causing the car to go into limp mode.

I find it really strange the pump failed seeing as the car only has 900kms on it but it's fixed now so that's all that matters.

06-09-2018, 10:48 AM	#1
Mr.DoubleB Drives: 2018 1LE/LS Join Date: Jul 2017 Location: Toronto Posts: 34	v6 NPP fuse pull limp mode I pulled the NPP fuse (F51) shortly after getting the car. I've put about 800 kms on it since I've bought it with mostly city driving with out issue. The first time I took it on a long highway drive was today and it went into limp mode with a CEL. I pulled over and shut the car off hoping it would just reset but it didn't. I put the fuse back in and restarted the car and it came out of limp mode but the CEL remains. Any ideas what the problem is? Has any body experienced this before? Should I take it to a dealer to reset the code or just unplug the battery?

06-09-2018, 11:49 AM	#2
2SSVERT Drives: 17 garnet red 2ss vert Join Date: Apr 2018 Location: Highland Village, Tx. Posts: 45	First thing you need to do is pull the fault code and see what's going on. Most auto parts stores will get you the code for free.

06-10-2018, 09:34 AM	#3
TedJS Drives: 2016 Camaro SS Join Date: Jul 2016 Location: Cleveland, OH Posts: 92	Why are you pulling this fuse again? Putting the car in sport mode keeps the exhaust valves open all the time. Good luck with your check engine lamp and subsequent diagnosis.

06-10-2018, 01:19 PM	#5
Mr.DoubleB Drives: 2018 1LE/LS Join Date: Jul 2017 Location: Toronto Posts: 34	I took it to the dealership but the service department was closing and the techs had already left. The service manager had a code reader and said it looked like some type of short in the fuel system but couldn't do anything about it until Monday. When I restarted the car after the manager looked at it, it had come out of limp mode and on the way home the CEL disappeared. I've been driving around the city today and it seems fine but I haven't had it back on the highway yet.

06-10-2018, 07:21 PM	#7
Wierd Harold Drives: 2017 2lt rs Join Date: May 2017 Location: Ontario canada Posts: 332	You have a problem still. The code will still be recorded in the history side of the pcm,best to get it looked at.

06-14-2018, 11:17 AM	#8
Mr.DoubleB Drives: 2018 1LE/LS Join Date: Jul 2017 Location: Toronto Posts: 34	So it turned out the high pressure fuel pump had failed and was causing the car to go into limp mode. I find it really strange the pump failed seeing as the car only has 900kms on it but it's fixed now so that's all that matters.

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