Operation CHARM: Car repair manuals for everyone.

Pass-Key

Disarming

The system may be disarmed by turning either outside Door Lock Cylinder to the "UNLOCK" position using the Door Key.

This applies ground to terminal "D15" of the CCM, gray connector, thus disarming the system.


Tampering

With the system armed, the Horns will sound "ON" & "OFF" if:

^ Either door is opened without key.
^ Hatch is opened.
^ Key is put in Ignition.
^ Park Lamps/Headlamps turned "ON."
^ Power Door Switch is moved to "LOCK" or "UNLOCK" position.

In addition to the Horns sounding, the Starter Enable Relay will be disabled; the ECM will not receive a Fuel Enable signal on the Serial Data Lines from the CCM to allow fuel injector pulses to begin; and the PASS-Key� Ignition Key will not be recognized.


CIRCUIT OPERATION


Resistor sensing contacts are located in the Ignition Key Lock Cylinder. These contact the Resistor Pellet on the Ignition Key when it is inserted. The Pellet resistance is read by the Central Control Module (CCM) by comparing it to a fixed resistance. A two-way connector connects the sensing contacts of the Ignition Switch to the CCM.

If the Key Pellet is the proper resistance, terminal "F4" of the CCM, green connector, grounds the Starter Enable Relay to energize it and allow Engine cranking. Also, a signal is sent to the Electronic Control Module (ECM) through the Serial Data Lines to allow fuel injector pulses to begin.

If the Key Resistor Pellet is the wrong value, there will be no outputs from the CCM to the Starter Enable Relay or the ECM. This state will last for approximately 3 minutes, even if a proper key is inserted. After the 3 minute wait, a proper key can be inserted to start the Engine.

If a problem is detected with the PASS-Key� System, the Security Indicator will be illuminated by the CCM.