B2958

Diagnostic Chart (Part 1 Of 2):

Diagnostic Chart (Part 2 Of 2):

Schematic:

CIRCUIT DESCRIPTION
The Personal Automotive Security System (PASS-Key II) is a vehicle theft deterrent system. The PASS-Key II is designed in order to prevent vehicle theft by disabling the engine from starting unless an ignition key with a specific resistor pellet code is used in the ignition lock cylinder.

The ignition lock cylinder contains the resistor-sensing contacts. These contacts touch the resistor pellet that is embedded in the ignition key. When the ignition key is inserted in the ignition lock cylinder, the resistor pellet completes the key detection circuit (CKT 1073 and CKT 1074).

When the ignition switch is turned from the LOCK or the OFF position to the RUN position, the BCM applies a 5 V reference voltage to CKT 1073.The BCM reads the resistor pellet code and compares the stored resistor pellet code against the ignition key resistor pellet code for a correct match.

When the BCM detects a correct match, the BCM sends a fuel-enable password to the Powertrain Control Module (PCM) through the Class 2 serial data link. The PCM enables the theft deterrent relay. This action allows fuel delivery to the engine.

CONDITIONS FOR SETTING THE DTC
^ The voltage detected in CKT 1073 by the BCM is high. This condition indicates that a short to B+ is present.
^ The condition is present during an engine start attempt.
^ The condition is present for 1 second anytime after the engine has started.

ACTION TAKEN WHEN THE DTC SETS
^ The BCM stores DTC B2958 in the memory.
^ The BCM sends a message to the IPC in order to turn on the SECURITY indicator through the Class 2 serial data link.
^ The BCM performs one of the two following actions:
- If CKT 1073 or CKT 1074 is open or shorted to voltage when attempting to start the engine, the BCM will NOT send a message to the PCM to enable the theft deterrent relay or to deliver fuel to the engine. The engine will exhibit an engine no-crank condition.
- If CKT 1073 or CKT 1074 is open is shorted to voltage after the engine has started, the BCM enters a fail-enable mode. Upon subsequent engine start attempts, the BCM sends a password message to the PCM via the Class 2 serial data link in order to enable theft deterrent relay and deliver fuel to the engine. The engine will start.

CONDITIONS FOR CLEARING THE MIL/DTC
^ The BCM detects a valid PASS-Key II resistance value on the PASS-Key II input circuit (CKT 1073).
^ A history DTC clears after 100 consecutive ignition cycles if the condition for the malfunction is no longer present.
^ Use a Scan Tool in order to clear the DTC.

DIAGNOSTIC AIDS
The following conditions may cause an intermittent malfunction to appear:
- Dirty or loose ignition cylinder key contacts
- A dirty key resistor pellet
- An open key resistor pellet
- An incorrect PASS-Key
- An intermittent open or short to B+ in CKT 1073 or CKT 1074
- An open in the ignition cylinder key contacts
- Poor connections at the BCM or the ignition lock cylinder
^ Ensure that the key resistor contacts are clean and free of grease and oil. These substances may interfere with the key detection circuit and set this DTC.
^ Inspect for an open or short to B+ in CKT 1073 or CKT 1074.
^ Inspect for poor connections at the BCM and the ignition lock cylinder assembly. Poor connections at these components may cause an open, short, incorrect PASS-Key II resistance or intermittent malfunction. If the DTC is a history DTC, the condition may be intermittent Perform the tests shown while moving the wires and connectors. This action may often cause the malfunction to reappear.
^ DTC B2958 may set in the BCM when the ignition switch is in the RUN position with the steering column lock and the ignition key cylinder connector (C207) disconnected. When the BCM diagnostics and repairs are completed for DTC B2960, clear the DTCs and perform the BCM Diagnostic System Inspect.
^ The DTC P1626 sets in the Powertrain Control Module (PCM) when the ignition switch is in the RUN position and the BCM is disconnected. When BCM diagnostics and repairs are completed, refer to Engine Controls for additional information on PCM-related DTCs.

TEST DESCRIPTION
The number(s) below refer to the step number(s) on the diagnostic table.
2. This step inspects if the PASS-Key II resistor pellet is within the allowable range.
3. This step determines if the BCM output voltage to the ignition lock cylinder is within the proper range.
4. This step tests for an open in CKT 1073.
10. This step tests for a short to B+ in CKT 1073.
12. This step tests for an open in CKT 1073.
14. This step tests for a short to B+ in CKT 1074.
16. This step tests for an open in CKT 1074.