Bus (+) &/Or Bus (-) Open Or No Response From Sentry Key Immobilizer Module

Possible Causes:

• Attempt To Communicate With The MIC
• Ground Circuit Open
• Fused Ignition Switch Output Circuit Open
• Fused B+ Circuit Open
• Open PCI Bus Circuit
• Sentry Key Immobilizer Module

Testing

1. Turn ignition on. Using scan tool, select BODY and ELECTRO/MECH CLUSTER. If scan tool is able to communicate with instrument cluster, go to next step. If scan tool is not able to communicate with instrument cluster, go to BUS (+) &/OR BUS (-) OPEN OR NO RESPONSE FROM INSTRUMENT CLUSTER  .
2. Turn ignition off. Disconnect Smart Key Immobilizer Module (SKIM) harness connector. See Figure . Using DVOM, check resistance between ground and SKIM harness connector terminals No. 3 (Black/Light Blue wire) and No. 5 (Black wire). If resistance is less than 5 ohms on each circuit, go to next step. If resistance is 5 ohms or more on either or both circuits, repair open as necessary.
3. Turn ignition on. Using test light connected to ground, probe SKIM harness connector terminal No. 4 (Dark Blue wire). See Figure . If test light illuminates, go to next step. If test light does not illuminate, repair open Dark Blue wire between fuse block and SKIM.
4. Turn ignition off. Using test light connected to ground, probe SKIM harness connector terminal No. 6 (Pink/Red wire). See Figure . If test light illuminates, go to next step. If test light does not illuminate, repair open Pink/Red wire between fuse block and SKIM.
   NOTE: Ensure other modules communicate on PCI bus before continuing. If one module does not communicate, go to appropriate test. If no PCI communication exists, go to PCI BUS COMMUNICATION FAILURE  .
5. Connect Scope Input Cable (CH7058) to channel one connector on scan tool. Connect Red and Black leads, and Cable-to-Probe Adapter (CH7062) to scope input cable. Go to next step.
6. Using scan tool, select PEP MODULE TOOLS, LAB SCOPE, LIVE, then 12-VOLT SQUARE WAVE. Press F2 for scope. Press F2 again and use down arrow to set voltage range to 20 volts. Press F2 again. Go to next step.
7. Connect Black lead to ground. Connect Red lead to SKIM connector terminal No. 2, PCI bus circuit (Violet/Yellow wire). Turn ignition on. See Figure . Observe voltage display on scan tool lab scope. If voltage pulses from zero to about 7.5 volts, go to next step. If voltage remains at zero volts, repair open Violet/Yellow wire.
8. If no other problems are found, replace SKIM. See SENTRY KEY IMMOBILIZER MODULE (SKIM)  under REMOVAL & INSTALLATION.