ewo1
SR. MEMBER - 99 Amtran RE DT466E HT 250HP-Md3060
those are some good questions, my response in red, above...What is a BAP (Barometric pressure sensor) and how does it relate to your codes that indicate problems with the APS/IVS? unknow as of this moment...still figuring it out.
Googling for 10 seconds showed me that a BAP was the baro pressure sensor. I'm going to SPECULATE based on the t444e/7.3 engines that I've worked on, that the BAP has nothing to do with those sensors, UNLESS they share a power or ground wire. YES THEY SHARE VCC AND GROUND The BAP will only change "with the weather". CORRECT
Your codes indicate a mismatch between the APS and IVS. CORRECT The computer is going to "expect" a certain APS when the IVS indicates idle position. CORRECT Isn't the IVS an on/off switch at idle? YES Doesn't the APS produce a couple of comparable voltages.... YES IT DOES ON A LINEAR SCALE, 0 - 5 VOLTS DEPENDING ON THE POSITION OF THE REOSTAT (VARIABLE RESISTOR)
CAUTION: Car info follows: some cars have one sensor that ranges from 0 to 5 volts while the other ranges from 5 to 0, they will always "mirror" each other with a voltage that totals 5 volts. If the computer ever sees a total that is NOT 5 volts, it has no idea where your foot is and gives you idle speed.
So how does your bus APS work? I speculate you will have two variable voltages from idle to WOT, CORRECT and one IVS that switches as the pedal moves from the rest position. CORRECT, ACTS AS AN ON/OFF SWITCH, IF YOU WILL...
So basically the IVS, used as an on off switch, is nothing but a hall effect sensor, tells the computer you are intentionally stepping on the gas pedal and it is ok now for the TCM to respond, spin the wheels....
the AVS is nothing but a simple adjustable resistor, the more you step on the peddle, the more voltage to the computer, computer responds by adjusting the fuel to get you going.
So how can the BAP or MAP interfere with the APS/IVS circuit. They both share power and ground on the same circuit...at least on my bus.
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