Help Needed With DTC.........

[thefinestimage]

Over the weekend my GF was driving my H2, and the check engine light came on. DTC P0651. I cleared it, started it, drove no light. Turned it back on, light came right on. Any ideas as to what it could be? Have an appointment next Monday to get it looked at. Wanted some ideas before going to the dealership. Still drives as it should, as if nothing is wrong. Any help, or info would be great. Thanks!

[Hummerguy32]

Definition of Diagnostic Trouble Code P0651
Category Powertrain
Definition Sensor Reference Voltage "B" Circuit/Open

[Hummerguy32]

DTC P0651

Perform diagnostic check of the vehicle. Now try operating the vehicle within the conditions for running the DTC and check if the DTC fails this ignition. With the ignition turned off, detach the air conditioning pressure sensor and check if the voltage is within the specified range. Now connect the air conditioning pressure sensor and detach the FTP sensor and check if the voltage is within the specified range. Perform trouble checking of the 5 volt reference circuits for a short to voltage. Find out the fault correct it. Also perform trouble checking of the FTP sensor signal circuit for a short to voltage. Find out the fault correct it. Change the FTP sensor and the air conditioning pressure sensor. If required also change the PCM. Clear the DTC?S using a scan tool and check if the DTC has been reseated.

[Easy Ed]

Out of 2003 Service Manual