For 1990-2009 cars
Body Control Module Components
Cell 51: SDM, Washer Solvent Lever Sensor, Seat Belt Switch and Park Brake Switch

### Circuit Description

This is a trouble code (both current and history) that indicates the ALC parklamp relay output is shorted to ground or open.

### Conditions for Setting the DTC

Meet all of the following conditions:

• | The ALC option is enabled and ignition one is active.

• | The ALC parklamp relay output is not active.

• | The ALC parklamp feedback is present for five seconds.

### Action Taken When the DTC Sets

• | Stores DTC B2587 in the body control module (BCM) memory.

• | The SERVICE VEHICLE SOON indicator will illuminate.

### Conditions for Clearing the DTC

• | The body control module (BCM) goes to sleep and reinitializes with the fault cleared.

• | All the body control module (BCM) history codes will be cleared after 100 ignition cycles (from OFF to ON) with no current codes active during the 100 ignition cycles.

• | Use the scan tool.

### Diagnostic Aids

If the DTC is a history DTC, the problem may be intermittent. Try performing the above tests while wiggling the wiring and connectors. This can often cause the malfunction to appear.

### Test Description

The numbers below refer to the numbers on the diagnostic table.

1. This verifies proper operation of the ALC parklamp.

2. This determines if a short to ground exists in CKT 1080 within the underhood wiring harness junction block.

3. This determines if a short to ground exists in CKT 1080 between the underhood wiring harness junction block and the BCM.

4. This determines if an open exists in CKT 1080 between the underhood wiring harness junction block and the BCM.

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
Important: A short to ground will cause an open fuse(s). Before performing this diagnostic procedure, inspect the fuse(s) for an open.
1 | Was the Body Control Module (BCM) System Check performed? | -- | Go to Step 2 | Go to Body Control Module System Check
2 |

1. Replace the ALC parklamp relay with a known good relay on the underhood wiring harness junction block.
2. Use the scan tool in order to enable the ALC parklamp relay.

Does the ALC parklamp relay work correctly?

--

Go to Step 10

Go to Step 3

3 |

1. Reconnect the ALC parklamp relay on the underhood wiring harness junction block.
2. Disconnect the underhood junction block connector C3.
3. Use the J 39200 DMM in order to measure the voltage in CKT 1080 between the underhood wiring harness jucntion block connector C3 terminal B8 and ground.

Is the measured voltage at the specified value?

B+

Go to Step 5

Go to Step 4

4 | Replace the underhood wiring harness junction block. Refer to Underhood Fuse Block Replacement in Engine Electrical. Is the repair complete? | -- | Go to Step 10 | --
5 |

1. Disconnect the body control module (BCM) connector C1.
2. Use the J 39200 DMM in order to measure the resistance in CKT 1080 between the body function controller (BCM) harness connector C1 terminal B1 and ground.

Is the measured resistance within the specified range?

Infinite

Go to Step 7

Go to Step 6

6 | Repair the short to ground in CKT 1080 between the body control module (BCM) connector C1 terminal B1 and the underhood wiring harness junction block connector C3 terminal B8. is the repair complete? | -- | Go to Step 10 | --
7 | Use the J 39200 DMM in order to measure the resistance in CKT 1080 between the body control module (BCM) harness connector C1 terminal B1 and the underhood wiring harness junction block harness connector C3 terminal B8. Is the measured resistance within the specified range? | 0-2ohms | Go to Step 9 | Go to Step 8
8 | Repair the open in CKT 1080 between the body control module (BCM) connector C1 terminal B1 and the underhood wiring harness junction block connector C3 terminal B8. Refer to Wiring Repair in Wiring Systems. Is the repair complete? | -- | Go to Step 10 | --
9 | Replace the body control module (BCM). Refer to the following procedures:

• | Body Control Module Replacement

• | Body Control Module (BCM) Programming/RPO Configuration

Is the repair complete?

--

Go to Step 10

--

10 | Clear the DTCs from the memory. Are the DTCs cleared from the memory? | -- | Go to Body Control Module System Check | --