GM Service Manual Online
For 1990-2009 cars only

Tools Required

J 39200 Digital Multimeter

Important: In order to prevent misdiagnosis, verify that no DTCs are stored in the PCM by performing the On-Board Diagnostic System Check. Look for DTCs that indicate a problem in the PASS-Key® II fuel enable circuit. Refer to Powertrain On Board Diagnostic (OBD) System Check or Powertrain On Board Diagnostic (OBD) System Check in Engine Controls.

The following are the most likely causes of intermittent starting or cranking complaints due to the PASS-Key® II:

    • Incorrect resistance measurement of the ignition key resistance
    • Intermittent relay

In order to test for incorrect resistance measurements, use the following steps:

    • If only one key functions properly, clean or replace the faulty key. If you have tried a key that did not function properly, you must wait 3 minutes for the Tamper Mode timer to expire. After 3 minutes you may try a new key.
    • If none of the keys function properly, one of the following conditions is present:
       - The lock cylinder is dirty or defective.
       - The key resistance circuit wiring, connections, or contacts are faulty.

Use the following steps in order to measure the key resistance circuit with an ohmmeter:

  1. Use the J 39200 in order to measure resistance across the key contacts while the key is removed from the vehicle.
  2. Disconnect the Body Control Module (BCM).
  3. Insert the key into the ignition.
  4. Set the J 39200 to MIN MAX.
  5. Measure the resistance across terminals C2 and D7 of the BCM harness connector C3.
  6. Rotate the steering wheel from side to side.
  7. Listen for an audible tone from the J 39200 . A tone indicates that the resistance is fluctuating.
  8. • If the resistance is fluctuating, inspect the wiring and the wiring connections to the lock cylinder for an intermittent condition. An example of an intermittent condition is a poor connection or a broken wire inside the insulation.
    • If the resistance is not within 5 ohms of the resistance measured on the key, inspect for a dirty or defective lock cylinder.
  9. In order to test for a resistance change, rotate the key to all possible positions. Monitor the results. A resistance change of over 5 ohms indicates a problem with the lock cylinder or the key contacts.

Use the following steps in order to test for intermittent relay:

  1. If the SECURITY indicator illuminates for the 5 second bulb check then goes out, inspect the relay. If the connections to the relay are OK, install a new relay.
  2. If the SECURITY indicator remains illuminated longer than the 5 second bulb check when the vehicle will not crank, the relay is not the cause of the condition.
  3. If you need to turn the key several times before the engine cranks, the relay is not functioning properly. Inspect the connections to the relay. If the connections to the relay are OK, install a new relay.

If you cannot start the engine immediately after a fault, the relay is not the problem. Complete the following steps:

    • Verify that the connector to the Body Control Module (BCM) is tight.
    • Verify that the connector terminals to the BCM are clean.
    • Inspect the powertrain control module (PCM) for DTCs. Refer to Powertrain On Board Diagnostic (OBD) System Check or Powertrain On Board Diagnostic (OBD) System Check in Engine Controls.
    • Manipulate the harness. Inspect the power and the ground to the module.
    • During an ignition cycle the SECURITY indicator will illuminate. The indicator will remain illuminated for at least 1 minute when a problem exists in the key resistance circuits. The indicator will go out when the condition stops.
    • In order to determine whether the BCM is intermittent, lightly tap the BCM. The BCM is not typically intermittent.