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The only time the Pcm should prevent starting is if the engine is already running.
The PCM controls a double start over-ride safety that does not allow the starter to be engaged if the engine is already running.
Here is info from the manual on the starting system. And after that is a diagram of the electrical for the starting system.
The starting system consists of:- Starter relay- Starter motor (including an integral starter solenoid)Other components to be considered as part of starting system are:- Battery- Battery cables- Ignition switch and key lock cylinder- Clutch pedal position switch (manual transmission)- Park/neutral position switch (automatic transmission)- Wire harnesses and connections.The Battery, Starting, and Charging systems operate in conjunction with one another, and must be tested as a complete system. For correct operation of starting/charging systems, all components used in these 3 systems must perform within specifications. When attempting to diagnose any of these systems, it is important that you keep their interdependency in mind.The diagnostic procedures used in each of these groups include the most basic conventional diagnostic methods, to the more sophisticated On-Board Diagnostics (OBD) built into the Powertrain Control Module (PCM). Use of an induction-type milliampere ammeter, volt/ohmmeter, battery charger, carbon pile rheostat (load tester), and 12-volt test lamp may be required.These components form two separate circuits. A high amperage circuit that feeds the starter motor up to 300+ amps, and a control circuit that operates on less than 20 amps.The PCM controls a double start over-ride safety that does not allow the starter to be engaged if the engine is already running.
REMOVAL For complete circuit diagrams, refer to the appropriate wiring information. The wiring information includes wiring diagrams, proper wire and connector repair procedures, details of wire harness routing and retention, connector pin-out information and location views for the various wire harness connectors, splices and grounds.