B2721

CIRCUIT DESCRIPTION
The Key Invalid check runs every time the PASS-Key (R) III Module internal processor detects a key in the ignition switch. The transponder data is read following key insertion and is compared to the learned data in EEPROM. Any data mismatch between the transponder code and the value stored in memory will cause this Diagnostic Trouble Code (DTC) to be set.

If this DTC is set, replace the key and reprogram the new coded key using the Auto-Learn procedure.

CONDITIONS FOR SETTING THE DTC
This diagnostic runs at ignition key insertion.

ACTION TAKEN WHEN THE DTC SETS
The fuel disable message will be sent to the Powertrain Control Module (PCM).

CONDITIONS FOR CLEARING THE MIL/DTC
This DTC will be automatically cleared when the module reads a valid key transponder code.

TEST DESCRIPTION
The PASS-Key (R) III Module contains a software program that performs an ignition key transponder check. The entire check is done within the PASS-Key (R) III Module. Key check results are reported over the Class 2 Data Link upon request from a Scan Tool.