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.
173 discussions on “Reduced Power Displayed 2003 Chevrolet Tahoe”
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The current AC Delco part number is PT2628. A search of that number should find a supplier.
Where can i purchase the repair harness for the throttle body. mine is due for a replacement
It sounds like your battery is dead or there is a poor connection at the battery. I would start by checking/cleaning the battery cable ends. Then I would charge the battery with a battery charger and have it checked to see if it is any good. Does your vehicle have an electronic throttle body or does it have a throttle cable?
Great information offered in the posts. I have a 2001 Tahoe LT 5.3. I’m torn on taking it the dealer or to my trusted mechanic. My truck just started acting up. My records indicated I had the the Throttle serviced in january 2008. I was parked on a hill and thought that was the problem. But I towed it to a flat service and still nothing. IThere are so many problem solving solutions I would think the dealer should have this nipped by now and shouldn’t be a problem to fix. My mechanic would have to go through the routine from smallest to biggest solution which could add up dollar wise. I put the key in the ignition and turn and nothing hapens and I hear a buzzing from behind the steering wheel. When AAA came, the guy connected the booster cables and it turned over. The first time he took them off, my trck shut off right away. The second time it stayed on. Pressing on the gas pedal barely did anything to rev it. I turned the car off scared to not mess anything else up. What should I do? I’m in Smyrna, west of Atlanta. The dealer is right around the corner. my mechanic is soouth of Atlanta by the airport. My funds are limited. I just want it fixed right the first time.
Dwayne
dwayneatl@yahoo.com
If your truck has the electronic throttle body, the throttle position sensor is part of the throttle body assembly and is non field serviceable.