This 2003 Chevrolet Tahoe with a 5.3 liter engine came in with the customer complaint of the reduced power display was on and the vehicle could not be driven more than about 30 mph. Checking codes found a code p1516 stored for Predicted VS. Actual Throttle Position Correlation Error. That is fancy computer talk for the computer expects the TPS to be in one position and it sees the TPS in another position. There are several things that can cause this condition but by far the most common is a faulty throttle body assembly. I have noticed a disturbing trend in these vehicles in that the last few that I have had to change I also found very weak batteries and the weaker the battery is during cranking the more pronounced the symptom. If the key was left on in these vehicles for more than about five to ten minutes (the time it takes to hook up a scanner and check computer codes and relative data), the starter would turn the engine over very slowly (indicating a weak battery) and sometimes the battery would have to be jumped to start the engine. I may be wrong but it is my belief that a weak battery condition during cranking may be leading to premature failure of the throttle body assembly. My personal philosophy on late model highly computerized vehicles is to replace the battery every three to five years regardless and of course use a good battery and not the cheapest you can find.
Anyways on to changing the throttle body assembly. First remove the upper engine trim cover by first removing the screw and lift off.
Next remove the intake tube that connects to the mass air flow sensor.
Now the intake hose from the throttle body assembly.
Disconnect the clip that holds the intake hose assembly to the radiator hose.
Remove the harness connector from the throttle body by first pulling the gray locking clip back. Depress the lever and remove the connector. Inspect the yellow wire for possible damage as it too can cause the problem, although it seems to be more of a problem in the full sized vans.
There are three nuts that have to be removed.
Next the coolant lines have to come off but first I clamped them both off with hose clamp pliers. Then I took the coolant hose spring clamp and moved it back down the hose so that I could remove the hose from the throttle body. One could use pliers with a little luck and a lot of frustration it will move.
After the hose, next to the alternator is removed the throttle body can be repositioned to make the rest of the job easier.
Off with the old and on with the new. First the passenger side hose is installed. Then the throttle body assembly is put back in place and the driver’s side hose is reattached. In the following picture you can see that I used two pair of hose clamp pliers for the job. It saves having to drain the coolant system and time is money.
Now it is time to put the hose clamp back in place.
The new throttle body is now installed and ready for the intake hose and top trim cover to be replaced.
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Sparky – excellent walk through. I just replaced the throttle body assembly on my 2003 Tahoe this evening. In reading through the comments, I noticed you mentioned recalibration to a user. I was confused if the recalibration you mention is recommended (my Tahoe has about 130k on original throttle body that was just replaced). Thank you!
You can buy them locally or on line. I would strongly recommend the AC Delco Brand. I would be hesitant to replace the connector unless I knew for sure it was faulty.
Where can i buy electronic throttle body and connector plus crimping tool
My best advice is to install a new AC Delco fuel pump assembly. It comes with a new updated harness connector. Install both, check for debris in the fuel tank, replace the fuel filter and fuel pump relay. If the truck sits for weeks at a time make sure it has non ethanol gas in it during that time. One last thing to check the integrity of the wiring circuits. Install a fused jumper wire (ATO or mini style) at the fuel pump harness between the larger black wire and the larger gray wire. Use a 20 amp fuse in the fused jumper wire. Remove the factory 20 amp fuse in the underhood fuse box and install a 25 or 30 amp fuse in its place. Turn the key on. If the wiring is good the 20 amp fuse in the installed fused jumper wire will blow immediately. If it is slow to blow or does not blow there is high resistance in the wiring that has to be corrected. High resistance in the wiring will produce a lower voltage for the fuel pump. DC electric motors will be damaged if they are operated on lower than designed voltage for an extended period of time. Do this test before the new harness connector is installed. Be Very Sure to re install the factory fuse in the underhood fuse box. Also make sure there are no fuel fumes while doing this test. The blowing fuse will produce a spark. The combination of Spark and Fuel fumes are explosive.
Hey sparky i have a 2001 chey tahoe lt with a 5.3 liter and ive been having a lot of trouble with my fuel pump lately! Ive replaced it 4 times in the last month! What its doing is sometimes when i go outside to start it i cant hear the fuel pump cut on so i have to beat on the tank while someone turns the key and then sometimes i go out side and try to start it and the pump comes right on! I checked all of my relay and fuses and they work great! The one thing i did not do is change the wiring harness when i changed the pump and the reason for that is because i used a test light to check the positive and negative wires going to the harness and everything checked out fine but i think im going to go ahead and change it anyways just to see what happens. Please respond back if you have any helpful tips on this issue! Thanks