I only have 4.5 volts on the MAP sensor circuit. I checked from +5v to MAP ground, and from +5v to chassis ground, both engine on and engine off. It's consistent across all of those scenarios. Is that low enough to cause a problem? What would cause low voltage on that circuit?I can check a LMM here in a bit basically it's same ecm arrangement= Baro sensor on the ECM. Check your 5v supply to Map the sensor to if it's low the MAP sensor will also read low.