Reduced Engine Power

parkprimus · July 12, 2009

I stupidly started my truck to move it while the airflow sensor was removed so that I could clean my air filter and filter box. After moving my truck I notice the error on the readout as I was turning my truck off but paid little attention to it and continued working on my truck. After I was done I wanted to take my truck for a spin but the error came on immediately as well as the check engine lite. My truck will only idle and the gas pedal does nothing. What can I do? Should I buy a scanner and if I do can I reset the codes to make the reduce engine power error go a way. I can not even get out of my drive way in idle because there is an incline. Any help will be much appreciated.

bill190 · July 12, 2009

Try disconnecting the battery for about 20 minutes, then reconnecting.

Also clear the code(s) with a scanner.

parkprimus · July 12, 2009

Try disconnecting the battery for about 20 minutes, then reconnecting.

Also clear the code(s) with a scanner.

I cleared the codes just waiting on the 20 min disconnect.

The codes are P0120,P0220 and P1516

P0120 = Throttle/Pedal Position Sensor A Circuit

P0220 = Throttle/Pedal Position Sensor B Circuit

P1516 = Electronic throttle module throttle postion

bill190 · July 12, 2009

Check the connector/wiring to a gizmo on the throttle body which would monitor how far open the throttle is.

This is called the throttle position sensor.

Follow the wire back to where it goes and be sure all connectors are snug.

BTW, did you get any cleaning fluid on this sensor? if yes, you may need to replace it???

parkprimus · July 12, 2009

I had the sensor covered while I was cleaning the air box.

"Check the connector/wiring to a gizmo on the throttle body which would monitor how far open the throttle is." Is this just after the airbox?

I disconnected the battery after clearing codes and the codes came back.

bill190 · July 12, 2009

This has nothing to do with the airbox. It would be at the top of the engine where the air goes into the engine itself and is called the throttle body.

When you step on the accelerator, this pulls on a cable which goes to this location. Then the "throttle" opens. This is the area to check.

There would be an electrical sensor on the side of the throttle which would measure how far open the throttle is.

This sends the information to the engine computer and the engine computer then adds more fuel because someone has stepped on the accelerator and wants to go faster...

bill190 · July 12, 2009

Acually because you have a 2006, you might not have what I described above???

See if you can follow where the accelerator pedal goes and any gizmos it activates...

parkprimus · July 12, 2009

This has nothing to do with the airbox. It would be at the top of the engine where the air goes into the engine itself and is called the throttle body.

When you step on the accelerator, this pulls on a cable which goes to this location. Then the "throttle" opens. This is the area to check.

There would be an electrical sensor on the side of the throttle which would measure how far open the throttle is.

This sends the information to the engine computer and the engine computer then adds more fuel because someone has stepped on the accelerator and wants to go faster...

Ok I will check.

bill190 · July 12, 2009

If there is no cable which physically connects from your accelerator pedal to the throttle on the engine and mechanically makes it operate, you then would have a "drive by wire" system! Everything electrically operated.

If this is the case, then look for anything connected to the accelerator pedal. Be sure connections are OK.

And same with at engine at the throttle body. Clean good dry connections.

Then if this is all electronic, I suppose it is possible something got wet and maybe blew a fuse. So might want to check all fuses. Check owner's manual for all fuse locations. How to check fuses...

http://www.dinosaurelectronics.com/Test_Fuse.htm

Then sometimes when electronic things get wet, they don't work, but they can dry out by the next day and work fine. If all else fails and you can't find any problems, might want to try sticking a fan in there to blow air on the electronic gizmos.

parkprimus · July 12, 2009

I checked all the fusses that could be related and then some. I checked all the connectors from the gas pedal to the throttle body and a they look fine (performed a wiggle test). So I am thinking I have a bad sensor or a pigtail that has a bad connection. I am stumped.

FYI.. This is a fully electronic throttle system, I wish it was mechanical because it would be a lot easier to fix.

ColoradoSkiCountry · July 12, 2009

It probably will not make a difference, but go ahead and disconnect the battery cables again from the battery, touch both the battery cables together, then re-connect. THEN go ahead and pull out and put back in each individual fuse. Then go ahead and try starting her again. it *might* work Good Luck!!!

parkprimus · July 12, 2009

I started off with the word "stupidly". Well stupidly was the absolute correct word. I covered the opening of the air intake with a rag and covered the sensor with a rag, then cleaned out the air box with the air compressor. Then I had to move my truck, so I moved it and changed my oil. Long story short, I did not actually remember removing both said rags, so I disconnect the air intake hose from the throttle body and there it was, my little blue rag. This is just another good lesson learned the hard way, I suppose. I am always very careful with tools under the bonnet, what goes under the hood comes out. How embarrassing!!!!, but I am glad I have my truck back. And thanks to everyone for your suggestions, and please feel free to ridicule me with no holds bared, I deserve it!

bill190 · July 12, 2009

Good news! (At least we were looking in the right area!)

So was the rag keeping the throttle from operating?

I at least got something out of this. I've read about these systems but didn't know any were out there in vehicles yet. On the way too is even "drive by wire" steering and brakes. No mechanical linkage, just electronics!

(Or is that out there now too?)

clutch810 · October 21, 2009

sorry to bring this thread back from the dead, but im having the same issue, except i didnt have a small blue rag, i had a bit of mud in my intake and from there mud came out the exhaust, does any one have an idea on how to fix it?

i just bought a 2002 gmc sierra 2500 hd 8.1 with an allison tranny, 6" procomp lift, really nice truck 98000 miles.

my friends and i decided to go mudding and we were messing around and i went head first into a pit, broke my grill and fan shroud, but i leveled out in the pit. and then realised we werent going to get out by going foward so i had to back out which ment sinking the front end....again and again. well its been 3 days since then and i go out to start it this morning,and the reduce engine power light and ses light came on, with the codes(these are hard codes) p1221 p1120 and interminit p1515 p1516

and now the trucks in limp mode, i can go only 15mph and 2k rpm