MAP and Barometer?

Hello, I would retrace your steps if you did the thermostat replacement, the codes setting (P0641) is actually a code for the 5-volt reference voltage of the MAP sensor, this and the other code for the Barometric pressure sensor are related. The ECM will either have a Baro sensor built right into the computer, or the ECM takes a reading of the atmospheric pressure using the MAP sensor at just Key On, before the engine starts. The code with the Baro sensor is "Barometric Pressure Sensor Circuit Low Voltage", so a missing, shorted, or low 5-volt reference which the MAP sensor uses (one of the 3 wires on the MAP sensor). The other two wires are Ground and Signal wires. Im am thinking the connector may just not be seated correctly, because no other sensors are setting a reference voltage code. I will post the wiring diagram so you can find the MAP sensor to check its connector. But I would go through and recheck anything you touched first, it would be great if this is just a loose connection. Remember that the pins inside connectors can spread, creating a poor or no contact.

Here are the wiring diagrams for the MAP sensor, and Baro. Service info has the vehicle listed with two different sensors, but in many cases the Baro reading is taken from the MAP sensor before the engine is started. But I posted the wiring diagrams for both, if they actually do have two sensors. Why was the thermostat replaced if I can ask? Was it setting any codes? Because it does have a heater circuit it looks like, which is a much more modern design than people are used to seeing.
You can also go into the live data of the engine computer with a scan tool and see what the MAP is reading under global/basic OBD2 data, because some manufacturers will put in a substituted value in scan data and it can be misleading. And please let us know what you find.

While I was out driving, the car started sounding an alarm and indicating it was hot. Engine light indicated needed new thermostat.

Ok, I was just curious. If your over heating problem is repaired and there are no codes setting for the thermostat, which it would set if there was an issue with the circuit inside the thermostat.

how can I share this with my Mechanic thru messages? Don't have email for him.

You can save the wiring diagrams from the posting. To save the diagrams, click on the diagram to open it up fully, then right click on the diagram and you should have the option to "Save Image As..." There you can save the diagram to a folder on the computer and print it out or save the diagrams to a flash drive or SD card to transfer the file. if you want to grab a screenshot, under the Start menu of Windows there is a program called Snip & Sketch, it will take a screen shot for you and then you can save it as a picture file. Hopefully this helps?

Right clicking on the diagram without opening it fully, you can also open the image in another Tab of your browers. There you can see the entire diagram.

Thanx 4 ur help, from "I only drive the thing"! )

Glad to help, if you run into any other issues or are uncertain of testing results, just ask, hopefully you get things sorted out pretty easily.

so, is the fact that the thermostat is "generic", is it ok 2 use?

As long as there are no codes for it or overheating issues, it sounds like the thermostat is ok. I know the oem factory ones are really expensive. Sometimes you need to go with an aftermarket part and hope for the best, but I think the 2nd issue is related to the repair in some manner. It looks like, in service info you need to get some PCV hoses out of the way and possibly some others. Along with moving other components or the wiring harness around. Thats why retracing your steps and the area you were working in is important.