I could not find any information pertaining to diagnostics of the starting system and the vehicle do have an immobiliizer system.
The PCM has a ground that is bolted onto the top of left front strut tower. For the starter to be grounded, it has to go through some components inside the PCM after all conditions for it to work are true.
Try grounding the Tan wire at the PCM terminal 31 to see if the starter cranks with the key. If it does not, you have an open in the circuit between the atarter relay.
Here are the description of the security system.
Vehicle Theft Security System (VTSS) monitors vehicle doors, ignition switch, power door lock circuits and trunk key cylinder to determine if Body Control Module (BCM) should sound horn, flash interior lights and headlights, and disable ignition system. BCM inputs for VTSS are divided into 2 sections: trunk area and passenger compartment.
VTSS incorporates Sentry Key Immobilizer Module (SKIM) system. SKIM system provides passive protection against theft. SKIM system sends a signal to PCM to disable engine operation if proper key is not used. Reprogramming or initialization must be performed if PCM, SKIM or ignition key is replaced.
VTSS deactivates garage door opener and trunk release button when armed. System is passively armed by opening door, locking door using power door locks and closing door. While system is arming, VTSS LED will flash rapidly for 15 seconds. Opening any door or turning the ignition key while light is flashing will abort arming process. After 15 second arming period VTSS LED will flash slowly to show system is armed. System can also be armed using Remote Keyless Entry (RKE) transmitter or locking doors with key. System will not arm if manual door lock knobs are used to lock door(s). VTSS system uses a Light Emitting Diode (LED) to indicate when the system is armed. VTSS LED is located in instrument cluster. VTSS LED is also used by SKIM to advise owner when system has been immobilized due to use of invalid ignition key. VTSS LED will stay on after attempted restart if invalid ignition key is used.
VTSS is equipped with a tamper alert signal, indicating VTSS has been triggered (vehicle has been tampered with). When either front door is unlocked with key or RKE, the horn will sound 3 times, indicating vehicle has been tampered with.
Body Control Module (BCM) monitors all door switches for input status. On Breeze, Cirrus and Stratus, 4 door switches, one located at each door, are used for BCM DOOR OPEN input signal. On Sebring Convertible, 2 door switches, one located at each door, are used for BCM DOOR OPEN input signal. On all models, 2 arm/disarm switches are used in VTSS system and are located on the back side of the door lock key cylinder. These switches use internal resistors to send a signal to BCM when requested by the operator by selecting arm/disarm functions. A problem in any passenger compartment switch will not allow the system to arm.
BCM monitors trunk lock switch for a closed circuit. If switch circuit opens (trunk is opened or switch is removed), BCM triggers alarm. If there is a malfunction in trunk lock switch, system will arm, but switch will not be monitored. If switch becomes functional while system is armed, it will be used as an input to BCM.
SKIM system has 4 basic components: SKIM, sentry key transponder (key), VTSS light, and PCM. When ignition is turned on SKIM sends a Radio Frequency (RF) signal to transponder (key). RF signal excites transponder chip in ignition key and chip responds returning a RF signal with secret key code. SKIM compares code to information stored in memory to verify a valid key is being used. SKIM sends valid key signal to PCM. If wrong or new key is used, SKIM sends invalid key signal to PCM. PCM then disables engine operation by zeroing-out the pulse width of the fuel injectors. SKIM also sends signal to instrument cluster to illuminate VTSS light. Reprogramming or initialization must be performed if PCM, SKIM or ignition key is replaced.
Tuesday, August 10th, 2010 AT 8:00 AM