Circuit Description
The body control module (BCM) supplies power to the Passlock sensor on CKT 1459.
When the Passlock sensor is powered and the ignition switch is rotated to the CRANK position, the hall effect security sensor will latch and provide a code to the BCM. The BCM will then compare this code to the code in the previous ignition cycle. If the latched value is the same as the last ignition cycle value, the test has passed. When the ignition switch is switched to the OFF position, the sensor is no longer powered and resets the sensor latch circuit.
In the next ignition cycle, the Passlock sensor waits for an ignition switch crank input and verifies the sensor code and compares the sensor code to the last stored valid code.
Conditions for Running the DTC
The ignition switch is cycled to CRANK, released to ON and then cycled to OFF.
Conditions for Setting the DTC
| • | The BCM turns the sensor power OFF for approximately 0.1 seconds when the ignition switch is turned OFF. |
| • | During the 0.1 second shut down of voltage, if the BCM senses battery voltage the DTC will set. |
Action Taken When the DTC Sets
| • | The vehicle will start and run. |
| • | The SECURITY indicator remains illuminated. |
| • | The SERVICE VEHICLE SOON indicator illuminates. |
Conditions for Clearing the DTC
| • | Current DTCs will clear after one ignition cycle if the malfunction is no longer present. |
| • | All of the BCM history codes will be cleared after 100 ignition cycles (from OFF to ON) with no current codes active during the 100 ignition cycles. |
Diagnostic Aids
| • | Inspect for a poor connection at the Passlock™ Sensor and the BCM. |
| • | If the DTC is a history DTC, the problem may be intermittent. Perform the tests shown while wiggling the wiring and connectors. This action often causes the malfunction to appear. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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Tests for the proper operation of the circuit in the low voltage range. If the voltage does not drop during ignition OFF, the 12v power circuit is shorted to voltage.
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Tests for a short to voltage in the 12v power circuit.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Theft Deterrent (VTD) Diagnostic System Check? | -- | Go to Step 2 | |
2 |
Does the scan tool display DTC B2948 as a current DTC? | -- | Go to Step 3 | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems |
|
Important: The use of DMM J39200 is crucial in this step because voltage may be measured for 10 milliseconds only.
Does the voltage measure near the specified value? | 0v | Go to Step 7 | Go to Step 4 | |
Test the 12v reference circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 10 | Go to Step 5 | |
5 | Inspect for poor connections at the BCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 10 | Go to Step 6 |
6 |
Important: Perform the set up procedure for the body control module . Replace the body control module. Refer to Body Control Module Replacement in Body Control Systems. Did you complete the replacement? | -- | Go to Step 10 | -- |
7 | Inspect for poor connections at the Passlock ™ sensor. Refer to and Testing for Intermittent Conditions and Poor Connections in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 10 | Go to Step 8 |
8 | Replace the Passlock™ sensor. Refer to Ignition Lock Cylinder Replacement - On Vehicle in Steering Wheel and Column. Did you complete the replacement? | -- | Go to Step 9 | -- |
9 | Perform the Passlock™ learn procedure. Refer to Programming Replacement Lock Cylinder, Body Control Module or Powertrain Control Module . Is the repair complete? | -- | Go to Step 10 | -- |
10 |
Does the DTC reset? | -- | Go to Step 3 | System OK |
