Circuit Description
The BCM provides the steering column control function which allows the column to be electronically locked or unlocked. The BCM provides two outputs, column lock drive (A) and column unlock drive (B) and a steering column lock relay control output. The BCM can apply a ground or battery output on the column lock drive (A) CKT 1603 or column unlock drive (B) CKT 1604 depending on the desired steering column lock motor position. The BCM uses the feedback switch in order to monitor the motor position and determine if the commanded position was accomplished.
The BCM controls the position of the steering column lock motor based on the following input information:
| • | Ignition position |
| • | Key IN ignition status |
| • | Key OUT of ignition status |
| • | Steering column lock feedback switch |
| • | PASS-Key® system |
| • | PCM password information |
| • | System voltage |
The BCM also monitors its circuitry for the column lock 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 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. |
| • | The PCM may disable fuel if vehicle speed is detected over 2.4 km/h (1.5 mph). |
| • | 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 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 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 supply voltage for the steering column lock motor through CKT 2540. If the BCM is unable to supply voltage to the steering column lock motor through CKT 2540, the BCM will set a DTC B2587. |
| • | Disconnecting the steering column connector C207 with the ignition in the ON position will cause the BCM to enter a Fail Enable Standby mode. The steering column will remain inoperative until the Fail Enable Standby mode is cleared. To clear this mode, disconnect the BCM fuse #25 for 15 seconds. |
| • | The BCM fuse #23 will become open if the steering column lock motor or the lock drive (A or B) circuits 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 control circuit.
-
This test checks if supply voltage is available on CKT 2540.
-
This test checks for a for a short to ground in CKT 2540.
-
This test checks for a short to ground in CKTs 1603 or 1604.
-
This test checks if the steering column lock/unlock motor is shorted to ground.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Were you sent here from the BCM Diagnostic System Check? | -- | ||
Check the BCM fuse #23. Is the BCM fuse #23 open? | -- | |||
Is the test light ON? | -- | |||
Is the test light ON? | -- | |||
With a test light connected to B+, prob the BCM connector terminals (harness side) A6 then A8. Is the test light ON in either circuit? | -- | |||
Is the test light ON in either circuit? | -- | |||
7 | With a test light connected to B+, prob the BCM connector terminal (harness side) A6. Is the test light ON? | -- | ||
8 | Check the steering column circuit for an intermittent malfunction. Refer to Diagnostic Aids. Was an intermittent malfunction found and repaired? | -- | System OK | |
9 |
Does DTC B2587 set as current? | -- | -- | |
10 | Locate and repair short to ground in CKT 2540 or in the I/P electrical center. Is the circuit repair complete? | -- | -- | |
11 | Locate and repair the short to ground in CKT 1603 or CKT 1604. Is the circuit repair complete? | -- | -- | |
12 |
Is the replacement complete? | -- | -- | |
13 |
Is the repair complete? | -- | -- |
