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Home >> Cadillac >> 1996 >> Fleetwood Base >> Repair and Diagnosis >> Accessories & Equipment >> Communication Devices >> Central Control Module >> Diagnosing & Repairing CCM DTCS >> DTC 42, Key Resistor Circuit (Circuit Shorted To Ground) >> Testing
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DTC 42, Key Resistor Circuit (Circuit Shorted To Ground): Testing

  1. Check ignition key resistor pellet resistance. If resistance is less than 307 ohms, replace key. Clear DTCs and check if DTC resets. If DTC resets, connect Tech 1 scan tool to Data Link Connector (DLC). Place mass storage cartridge 3000003 into Tech 1. Turn ignition switch to RUN position. Read PASS-Key II(R) A/D counts. If counts displayed are not 28 or less, go to step 3). If counts displayed are 28 or less, no problem is found. Problem may be intermittent. Go to next step.
  2. Turn ignition switch to OFF position. Check for poor connections at CCM connector. If connections are okay, reconnect CCM connector and all other components. Clear DTCs and check if DTC resets. If DTC resets, replace CCM. If DTC does not reset, problem may be intermittent. Try to recreate fault while performing test by wiggling wiring and connectors. Check for poor connections at all connectors that may be causing intermittent condition.
    WARNING: Vehicle is equipped with air bag supplemental restraint system. When locating 2-pin ignition switch lock cylinder harness connector at base of steering column, DO NOT confuse connector with Yellow 2-pin air bag supplemental restraint system connector also located at base of steering column.
  3. Disconnect 2-pin ignition switch lock cylinder harness connector at base of steering column. Read PASS-Key II(R) A/D counts. If counts displayed are not 28 or less, replace ignition lock cylinder in steering column. If counts displayed are 28 or less, go to next step.
  4. Turn ignition switch to OFF position. Using DVOM and Adapter (J 35616-A), measure resistance between 2-pin ignition switch lock cylinder harness connector (CCM side of harness) terminal "A" and ground. If resistance is 5 ohms or less, repair short to ground in PASS-Key II(R) input circuit. If resistance is not 5 ohms or less, go to next step.
  5. Using DVOM and Adapter (J 35616-A), measure resistance between 2-pin ignition switch lock cylinder harness connector (CCM side of harness) terminal "B" and ground. If resistance is 5 ohms or less, repair short to ground in PASS-Key II(R) return circuit. If resistance is not 5 ohms or less, go to next step.
  6. Problem may be intermittent. Try to recreate fault while performing above tests by wiggling wiring, connectors and ignition lock cylinder. If all checks are okay, clear DTCs and check if DTC resets. If DTC resets, replace CCM.
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