Hyundai Repair: re: speed sensor, vehicle speed sensor, powertrain control

Question
What I meant was the airbag computer is original but the main computer (pcu?) was a remake.  I know the car has a recall about the airbags.  I have noticed that my scanner says a lot of the monitors aren't ready.  I haven't cleared the codes or removed the neg battery cable.  Shouldn't the computer have learned this by now?  My scanner says the tests are incomplete for the egr,o2, and evap.  Could the reman computer be the problem?  I dunno if this helps you but the scanner says module 11$ then the p0500.  What is left to replace.  The wiring looks ok to me.  How much are computers for this car?  Someone said it might have not been flashed before being installed?  I dunno.  thnaks

Answer
If the PCM (Powertrain Control Module, also ECM) is remanufactured, I'd be very suspicious that it's the cause of your issue.  You should expect this computer to cost you in the neighborhood of $1100.  It's entirely possible that this is the wrong computer for the vehicle.  Other vehicles use the same engine/trans setup, but the trans has a different final drive ratio.  If that were the case, you'd set the p0500 because the computer sees that the input speed sensor and output speed sensor correlate, but the vehicle speed sensor doesn't correlate with the output speed sensor.  But $1100 is quite a bit of money.  You should probably make sure the problem isn't in the wiring (i.e. check it electrically) before you go replacing the PCM.  

Hyundai PCM's aren't flashable other than performing updates supplied by the manufacturer.  You could try having it reprogrammed by a dealer-- there's a tsb (02-36-037) to reprogram the PCM for P0139 or a cold start hesitation-- and see if the code magically disappears.  Let the dealer know what you're trying to do so they can choose the proper PCM number for the car rather than doing an auto-reprogram or reading the number from the PCM itself.  The downside of this is that if there's an error in the process, the car won't run and you *will* need to replace the PCM.

You said a couple questions ago that if you clear the engine lamp, it comes back in two trips.  Depending on how long it's been since this was done, and what type of driving has been done, it may be quite normal that the EGR, O2, and evap tests haven't run.  In fact, the computer may be unable to run them if it cannot determine how fast the vehicle is going.