Circuit Description
The BCM provides the steering column control function which allows the column to be electronically locked or unlocked. The BCM can provide a ground or battery output on the column lock/unlock drive (A) circuit (CKT 1603) depending on the desired steering column motor position. The BCM controls the position of the motor based on input information, including the ignition position, the key-in-ignition status, and the system voltage, and information sent from the steering column feedback switch, the PASS®-Key system, and the PCM. The BCM uses the feedback switch in order to monitor the motor position and determine if the commanded position was accomplished. The BCM also monitors its circuitry for the column lock/unlock drive (A) circuit. If the BCM detects a malfunction present a DTC will set.
Conditions for Setting the DTC
| • | The BCM detects an internal malfunction (an open or a short to ground) in the column lock/unlock drive (A) circuit. |
| • | There is and open in the BCM voltage supply CKT 2540. |
| • | The condition must be present for 100 ms. |
Action Taken When the DTC Sets
| • | Stores a DTC B2587 in the BCM memory. |
| • | Sends a message to the IPC to display the SERVICE COLUMN LOCK message. |
Conditions for Clearing the DTC
| • | The BCM no longer detects an internal malfunction (an open or a short to ground) in the column lock/unlock drive (A) circuit. |
| • | Supply voltage is available on CKT 2540. |
| • | A history DTC will clear after 50 consecutive ignition cycles if the condition for the malfunction is no longer present. |
| • | Use the IPC clearing DTCs feature. |
| • | Use a scan tool. |
Diagnostic Aids
| • | The following conditions may cause an intermittent malfunction: |
| - | There is an intermittent open in BCM power CKT 2540. |
| - | The steering column lock/unlock drive (A or B) are shorted together or to ground. |
| • | A short to ground in CKT 2540 will cause BCM fuse #23 to open. The BCM receives supplies voltage for steering column lock/unlock motor through CKT 2540. If the BCM is unable to supply voltage to the steering column lock/unlock motor through CKT 2540, the BCM will set a DTC 2587. |
| • | Disconnecting the steering column connector C207 with the ignition in the ON position will cause the BCM to enter a fail enable mode. The steering column will remain inoperative until the fail enable mode is cleared. To clear this mode, disconnect the BCM fuse #25for 15 seconds. |
| • | The BCM fuse #23 will become open if the steering column lock/unlock drive (A or B) are shorted together or to ground. |
| • | If the DTC is a history DTC, the problem may be intermittent. Perform the tests shown while moving related wiring and connectors. This can often cause the malfunction to occur. |
Test Description
The numbers below refer to the step numbers on the diagnostic table:
-
This test determines if there is a short to ground in the column lock/unlock circuit.
-
This test checks for a short to ground in CKT 2540.
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This test checks for a for a short to ground in CKT 1603.
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This test checks for a short to ground in CKT 1604.
-
This test checks for a for a short between CKT 1603 and CKT 1604.
-
This test checks if the BCM can properly control the steering column lock/unlock motor.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Were you sent here from the BCM Diagnostic System Check? | -- | ||
Check the BCM #23 fuse. Is the BCM #23 fuse open? | -- | |||
Is the test light ON? | -- | |||
Is the test light ON? | -- | |||
With a test light connected to B+, prob the BCM connector terminal (harness side) A6. Is the test light ON? | -- | |||
At the harness side of the BCM connector C2, check for continuity between terminals A8 and A6. Is there continuity? | -- | |||
Is the test light ON in both the locked and unlocked positions? | -- | |||
8 | Check the steering column circuit for an intermittent malfunction. Refer to Diagnostic Aids. Was an intermittent malfunction found an d repaired? | -- | ||
9 |
Does DTC B2587 set as current? | -- | ||
10 | Check for an open in CKT 2540. Was a problem found and repaired? | -- | ||
11 | Locate and repair short to ground in CKT 2540 or in the electrical center. Is the circuit repair complete? | -- | -- | |
12 | Locate and repair the short to ground in CKT 1603 or CKT 1604.Was a problem found and repaired? | -- | ||
13 | Locate and repair short between CKT 1603 and CKT 1604. Is the circuit repair complete? | -- | -- | |
14 | Replace the steering column lock/unlock motor. Is replacement complete? | -- | -- | |
15 |
Is the replacement complete? | -- | -- | |
16 |
Are all DTCs cleared? | -- | -- |
