Need info- P1516 code
 

My 03 2500HD 6.0 has went into limp mode twice this year. The codes got erased before I could look at them last time. This time I come up with a P0300 which is engine misfire detected. Not sure where to start with that one. Just put new plugs and wires on a couple months ago.

Then I also had this P1516 code- Electronic Throttle Mod VS Throttle Position Sensor. I have read alot of different theories on this. From a wire on the throttle body to the gas pedal sensor to a ground wire. There were a few more but that is all I can remember at this time. Does anyone have anything solid on this issue. The truck would only run about five mile an hour in limp mode. Shut the truck off for about 20 minutes and started back up and everything was fine. No more check engine light and it drove just fine.

Also another thing has been happening and not sure if any of it is related. When going down the interstate usually between 65-75 the check engine light will flash about ten times. I usually back off the throttle when it starts flashing and it will go off until I pick speed back up. I don't know if this is related but I have read the same theories as stated above with one of them also being that the cats are bad/plugged. I may have to just take it to the dealer. This following is from a site that I copied it from.

"YOUR VEC. HAC ELECTRONIC THROTTLE BODY UNIT SO IT USES VOLTAGE SIGNALS TO CONTROL THROLLTE BLADE IN THE THROTTLE BODY. WHAT I HAVE SEEN ON THE JOB IS A FEW DIFFERENT ISSUES THAT CAN CAUSE THIS PROBLEM. FIRST OFF THERE IS A UPDATE FOR THE PCM TO ADDRESS THOSE CODES, BUT YOU WILL HAVE TO TAKE IT TO THE DEALER FOR THAT. SECOND THERE IS ISSUES WITH THE ACTUATOR ON THE THROTTLE BODY BINDING UP AND CAUSING THE CODES. THIRD THERE IS A YELLOW WIRE COMING OFF THE THOTTLE BODY CONNECTOR THAT BREAKS INSIDE INTERNALLY AND CANNOT BE SEEN TO THE NAKED EYE. THE BEST WAY TO TEST THAT IS TO GRAB THE WIRE ABOUT 5 INCHS FROM THE CONNECTOR AND TUG IF IT FEELS SPONGY OR BREAKS THATS YOUR PROBLEM. fOURTH THERE IS A GROUND AT THE BACK OF THE PASS. SIDE HEAD THAT BECOMES LOOSE. WHEN I GET ONE OF THESE VEC.S IN MY SHOP I UPDATE THE PCM REPLACE THE THROTTLE BODY UNIT AND CONNECTOR TO IT AND CHECK THE GROUND ON THE BACK OF THE HEAD IF I DON'T DO ALL OF THIS THAT ***** SEEMS TO ALWAYS COME BACK."

Re: Need info- P1516 code
 

Has anyone come across this same issue?

Re: Need info- P1516 code
 

secondary ignition leaking a magnetic field into harness?

don't forget the bulkhead connector by firewall that gets water in it and ruins connections.

also keep in mind the idea of contact "fretting". unplug and inject small amount of dielectric grease, then reconnect. Low current signals are very prone to this

Re: Need info- P1516 code
 

Still having this issue. The truck has went into limp mode four times in the last month. Pull over, shut it off for a minute, start back up and go again. It has never went into limp mode again after restarting in the same day.

Re: Need info- P1516 code
 

Throttle position sensors very common on the fly by wires. It is inside the throttle body and your local dealer should have the part. Dont know that the aftermarket is producing these yet.

Re: Need info- P1516 code
 

Found these videos on the issue.