Hyundai Repair: throttle problem., hyundai elantra, transmission control module

Question

throttle   QUESTION: I have a 1999 hyundai elantra, 2.0 4 cylinder engine. my throttle is missing either a cable or a wire, and I need to know exactly what it is that I need so I can ask for a specific repair when I find a mechanic in this state. I just moved out of state and dont have a mechanic that I normally go to yet.  The person that pointed it out was surprized that my car was even running without it. my check engine light came on at a friends house, he had a friend read the code and he cleared the code after. here is what I know, whatever cable/wire of the throttle that is in control of the "in" is there, the part that is in control of the "out" is what is missing (gone completely).. it is causing problems with my engine (one of the codes was from that) since he reset the codes, I cant get the code again until the check engine light comes on again. so, I figured instead of waiting and chancing engine damage (because what goes in must come out) during the wait that I would ask and see if you could help specify exactly what my throttle is missing. I personally have no idea what to look for to know what isnt there. but it is obvious that something is missing because there is an empty spot where there should be something connected. If I knew the specifics of a throttle I could figure it out, but I dont know how many cables, wires, etc are supposed to be there.. If you need anymore pics, just let me know  and I will send them..thanks in advance

ANSWER: Hi, Dot.  Your photograph shows what is called the idle position switch.  The transmission control module (TCM) used input from this switch on some cars to determine when the throttle was completely closed (foot off accelerator).  

As I look through the schematics, I don't see any reference to the switch on 1998 and later Elantras.  On the other hand, there is a technical service bulletin which indicates the switch, although present, was not used on Elantras built June 1, 1999 and later.  As I look at the parts catalog and examine the interchangeability of the various TCM part numbers, it seems to suggest that the bulletin is correct and not the schematic.  In addition, if you have a manual transmission, this switch is also not used.

On automatic transmission vehicles where the switch is not used, the TCM infers whether the throttle is closed based on throttle position sensor (TPS) readings that are imported from the engine control module (ECM).  

The typical symptom of the switch not being connected is that you'll have a noticeable downshift to first (a small thump-type sensation) as you come to a stop.  Normally, if the TCM senses that the throttle is closed, it'll only downshift to second gear.  Only when the throttle is applied to accelerate from the stop will it downshift to first.

It's my supposition that the check engine lamp had nothing to do with this switch being not connected.  If you can find out from your friend (or his friend) what the trouble code number was, I'll be happy to tell you what the code means and assist you in finding a solution.

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throttle   QUESTION: i figured it out. I am missing the cable (I attached a pic).. also, with my other question could it be the v belts? they scream when it acts up and stop screaming when it goes back to normal. they dont scream when the power slows though.. the belts are as old as the new alternator but I used belt conditioner often last winter to stop the squealing. they have a little build up from the spraybelt conditioner.  if it is definently the voltage regulator, around how much is it to fix? thanks  

Answer
If your vehicle does not have cruise control, you'll only have one cable.  With cruise control it should have two, one going to the accelerator pedal inside the car, and one going to the cruise actuator under the hood.

While a loose belt can cause charging problems, it cannot cause an overvoltage condition.  The fact that you have a code for excessive voltage means that the problem is in the voltage regulator and that you'll need to replace the alternator again to fix the issue.  The price for replacing the alternator will vary greatly by geographic location, the source of the parts used, and the shop doing the work, so I cannot tell you how much this will cost.  Use your previous bill as an estimate and call a few places near where you are not for other estimates.  This will get you a much better idea than I can provide.

If you have belt squeal, the alternator belt is most likely not tensioned tight enough.  You can correct this when the alternator is replaced.  The alternator belt on your vehicle needs to be tighter than on most other vehicles, so many mechancis who are not familiar with Hyundais often do not tighten them enough.