2002 trailblazer p1275 p1280

[Trailblazin94]

Ok so just recently had the fuel pump fail on me and replaced it with a new one. Started it up ran fine then I see "Service Engine Soon" and "Reduced Engine Power" when i went to give it gas i had zero throttle response, and threw me the code P1275 and P1280 both something to do with the APP sensor in the gas pedal. I replaced the gas pedal with a new GM one and still nothing has changend. I hear a weird noise from the throttlebody when I put the car into the on position. Is it worth replacing the throttle body when im not sure if that it? Or better of sending to my mechanic to have him figure it out? It all worked fine before the fuel pump stopped working.
Any suggestions would be much appreciated.
Thank you,
-Mark

 

[KNBlazer]

I would disconnect the battery for at least 30 minutes, clean throttle body while waiting, then see what happens....

if this doesn't take care of the prob, then it might be a harness issue, here I am of no help...

 

[MAY03LT]

Welcome to the site!

Here's a brief explanation of what sets those codes:

P1275 - The APP sensor 1 voltage is less than 0.13 volts or more than 4.87 volts.
P1280 - The APP sensor 2 voltage is less than 0.13 volts or more than 4.87 volts.

If you're familiar with testing circuits with a DMM, the wiring to these sensors can be tested.

There are two things that caught my attention when looking at the schematic.

1 - The fuel pump sending units low reference circuit is shared with both of the APP sensors
2 - The Fuel Tank Pressure sensors 5v reference is shared with APP2

So two things that could be tried without doing any real testing is to unplug the FTP and the fuel pump and see if the REP light goes out.

 

[Trailblazin94]

Bad news, the computer is shot

 

[IllogicTC]

Bad news, the computer is shot

And good news, now that you know the problem it can be fixed already instead of still being stuck in the troubleshoot phase.

 

[colefireangel]

Welcome to the site!

Here's a brief explanation of what sets those codes:

P1275 - The APP sensor 1 voltage is less than 0.13 volts or more than 4.87 volts.
P1280 - The APP sensor 2 voltage is less than 0.13 volts or more than 4.87 volts.

If you're familiar with testing circuits with a DMM, the wiring to these sensors can be tested.

There are two things that caught my attention when looking at the schematic.

1 - The fuel pump sending units low reference circuit is shared with both of the APP sensors
2 - The Fuel Tank Pressure sensors 5v reference is shared with APP2

So two things that could be tried without doing any real testing is to unplug the FTP and the fuel pump and see if the REP light goes out.

I'm having this problem. But I don't think it's my computer. I unplugged the fuel tank fuse and the REP light is still on. Looking for the FTP first now

 

[colefireangel]

Oops. Didn't mean to send that yet. Can't figure out how to edit it so.. anyway. Looking for the FTP fuse now, any help would be great. Thank you

 

[Mooseman]

This is a very old thread. I would suggest that you start your own with your vehicle info, circumstances and what's been done so far.

 

[colefireangel]

I can't seem to figure out how to do that