Need help with 03 ford windstar charging system. About a week and a half ago the van started revving high out of the blue and the overdrive light began flashing and the cel came on. Ran the codes, and they were all high voltage codes (high tps output, o2 sensor circuit, and about 6 others that were all voltage related). Checked battery voltage at 12.56, and running voltage ranging from 14.5-14.9v at varying times, typically the highest after driving for a bit and when electrical going crazy. Replaced alternator and van ran perfect for about 4 days and am right back where I started with the exact same codes and symptoms and all. I understand the voltage regulator is controlled by the bcm, but not 100% sure what exactly I should be looking for. I have looked inside the electrical harness that goes in the alternator and none of the prongs seem loose or corroded. Where should I go from here?
Don't have a whole lot to go by here, But it sounds more like the problem may lie in the PCM, not the alternator. The output of the alternator is within the normal operating band. What are the actual codes?
Exact codes are p0340(cam sensor circuit), p0113(intake air temp sensor circuit high input, p0118(ect circuit high input), p0123(tps circuit high input), p0708(transmission range sensor circuit high input), and p0453(evap emission pressure sensor/switch high input).
Any other ideas besides replacing my pcm with no way of determining that it is in fact bad? I know there are 2 wires in the alternator plug that communicate between the bcm, does anyone know what the particular voltage of each of those wires should be going to the bcm and back to the alt? Surely someone on here is a skilled ford mechanic experienced in electrical, right? Or at least access to this info maybe? Im currently stumped.
If you look up the diagnostics and possible causes, pretty much they have 3 common denominators: short in the system, poor ground, and failed PCM. Given the age, I'd be looking more for the ground or shorts. Pay particular attention around your belt.
It's tough to tell, the circuits will travel in the same loom through the harness. The first thing I'd do would be a physical check, basically a hand over hand with a flash light, looking for corrosion\deterioration at terminations and anything wearing through the loom. If nothing shows up, check voltage going to the sensors, it should be about 5 VDC.
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