03 grand am powers up "lights,radio,etc.turn the key nothing
Why would you do 10 minute key trick ? Is the SECURITY light on steady ? Just a code reader ? Checks just Engine PCM codes ! Need a professional type scan tool to check codes in the BCM - body control module ! Don't know what and how much you know about these GM vehicles ? The ignition switch is a low voltage input to the BCM ! To determine power mode , off ,ACC , run , crank
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 BCM. The PMM receives 3 discreet ignition switch signals to differentiate which power mode will be sent over the Class 2 Serial Data circuit.
To determine the correct power mode the PMM uses the following circuits:
• Ignition 0
• Ignition 1 voltage
• Ignition 3 voltage
Discrete Ignition Signals
Those modules that have discrete ignition signal inputs also remain in the state dictated by the last valid PMM message received on the serial data circuits. They then check the state of their discrete ignition input to determine the current valid state. If the discrete ignition input is active, battery positive voltage, the modules will fail-safe to the RUN power mode. If the discrete ignition input is not active, open or 0 voltage, the modules will fail-safe to OFF-AWAKE. In this state the modules are constantly checking for a change status message on the serial data circuits and can respond to both local inputs and serial data inputs from other modules on the vehicle . If you don't know anything about this your best bet , take it to a GM dealer . Without knowing what state the BCM is in or seeing from the ignition switch or if DTC'S - diagnostic trouble codes are stored , can't give you any sound advice . Would only be guessing !
May 31, 2017 |
2003 Pontiac Grand Am