2005 Pontiac Grand Prix no crank, no start.
not getting any comms through my obd2 scanner ?? What kind of scanner ? Full function one that can communicate with all the computers (modules) on the vehicle ? BCM ,IPC,HVAC etc.. Do you know how the electronics work on this vehicle , what happens when you turn the key to start?
Circuit Description (Key Start)
For ignition switch power modes refer to Body Control System Description and Operation in Computer/Integrating Systems. When the ignition switch is placed in the Start position a discrete 12 volts signal is supplied to the body control module (BCM) notifying it that the ignition is in the Start position. The BCM then supplies a class 2 message to the engine control module (ECM) / powertrain control module (PCM) notifying it that CRANK has been requested. At the same time the BCM is supplying 12 volts for the IGN 1 Relay / IGNITION MAIN PCM Relay closing it and supplying battery positive voltage for the CRANK Relay / STRTR Relay coil. The ECM/PCM verifies that the transmission is in Park or Neutral. If it is, the ECM/PCM grounds the control circuit of the CRANK Relay / STRTR Relay. When this occurs battery positive voltage is supplied through the switch side of the CRANK Relay / STRTR Relay to the S terminal of the starter solenoid.Do you know what power moding is ?
Power Mode Description and Operation
Power to many of this vehicle's circuits are controlled by the module that is designated the power mode master (PMM). This vehicles PMM is the body control module (BCM). The PMM controls which power mode (Run, Accessory, Crank, Retained Accessory Power, or Off) is active.
Serial Data Power Mode
On vehicles that have several control modules connected by serial data circuits, one module is the power mode master (PMM). On this vehicle, the PMM is the body control module (BCM). The PMM receives 3 discrete ignition switch signals to differentiate which power mode will be sent over the Serial Data circuits.
Relay Controlled Power Mode
The body control module (BCM) uses the discrete ignition switch inputs ignition 1, ignition 3 and crank to distinguish the correct power mode. Once the BCM has determined the power mode selected by the vehicle operator it will energize the Ignition relay, Run relay and retained accessory power (RAP) relay, depending on which power mode is selected.
Ignition 1 Relay
The relay uses a Hot At All Times B+ power source derived from the underhood electrical center. The ignition 1 relay supplies a power signal to the following circuits when the Run or Crank power mode is selected:
• AC clutch relay
• ABS STG angle sensor
• Antilock brake system (ABS) yaw sensor
• Auxiliary power drop connector
• Crank relay
• Cruse control switch
• Electronic brake control module (EBCM)
• Engine control module (ECM)
• Heating, ventilation, and air conditioning module (HVAC)
• Ignition control module (ICM)
• Instrument panel cluster (IPC)
• Sensing and diagnostic module (SDM)
• Transmission solenoid circuit
Retained Accessory Power (RAP) Relay
The RAP relay is energized when the Run or Accessory power mode has been selected. The relay uses a Hot At All Times B+ power source derived from the underhood electrical center. The B+ power source is protected by the 50 Amp BATT MAIN 2 fuse. The BCM also energizes the relay for 10 minutes after the vehicle operator transitions the ignition switch from Accessory to OFF or Run to OFF positions. The following circuits are controlled by the RAP relay:
• Power sunroof
• Power windows
Your best bet , take it to a qualified repair shop .