[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.