2001 Dodge Ram- 4x4- 5 speed manual- 5.9 l diesel
Code P0237----engine idles fine--no load will rev up to higher rpms but slowly
under load no power---code says MAP sensor low voltage--installed new sensor( didn't help)
Any ideas???? Thanks gregjo1948

 

Check and see that you are getting a proper 5 volt reference signal to the sensor.
Make sure the vacuum port it draws from isn't plugged. Also check the line between port, and sensor.

 

I don't have a vacuum line going to the sensor.

 

Where does it get it's vacuum signal from?

 

I think that is the job of the MAP sensor.

 

It is, but, in order for it to tell the PCM what manifold absolute pressure is, it has to have a port exposed to manifold vacuum/pressure, in order to read it.

 

The MAP sensor screws directly into the manifold. As the pressure within the manifold changes, the sensor senses the change and relays it to the PCM. That's how I understand it.
I've been wrong before!!!

 

Ok, that seems reasonable. Is the port into the manifold clean?

 

Yes it's clean. I checked it when I installed the new sensor.
I'm wondering if the problem might be a faulty TPS.

 

have a read here.