Circuit Description
The body control module (BCM) turns on the auto park lamp control relay when the ambient light sensor senses a dark condition. Battery positive voltage is supplied to the auto park lamp control relay at all times through the PARK LPS fuse. The BCM grounds the auto park lamp control relay control circuit in order to activate the relay.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC B2587 Parklamp Control Circuit Low
Conditions for Running the DTC
| • | The ignition switch is in the ON position. |
| • | The ambient light sensor senses a light condition (ALC park lamps OFF). |
Conditions for Setting the DTC
| • | The auto park lamp control relay control circuit is shorted to ground or open for 5 seconds. |
| • | ALC is not in operation. |
| • | The headlamp switch is not in the PARK position. |
Action Taken When the DTC Sets
| • | The SERVICE indicator will illuminate. |
| • | The check gages chime sounds. |
Conditions for Clearing the DTC
| • | The conditions for setting the DTC are no longer present. |
| • | A history DTC clears after 100 malfunction free ignition cycles. |
| • | The BCM receives the clear code command from the scan tool. |
Diagnostic Aids
If the DTC is a history DTC, the problem may be intermittent. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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Listen for an audible click when the auto park lamp control relay operates. Command both the ON and OFF states. Repeat the commands as necessary.
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Tests for voltage at the coil side of the auto park lamp control relay. The PARK LPS fuse supplies battery positive voltage to the coil side of the auto park lamp control relay.
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Exterior Lights Schematics Connector End View Reference: Master Electrical Component List in Wiring Systems | |||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information |
Does the auto park lamp control relay turn ON and OFF with each command? | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | Go to Step 3 | |
Does the test lamp illuminate? | Go to Step 4 | Go to Step 10 | |
4 |
Does the test lamp turn on and off? | Go to Step 8 | Go to Step 5 |
5 | Is the test lamp illuminated? | Go to Step 6 | Go to Step 7 |
6 | Test for a short to ground in the control circuit of the auto park lamp control relay. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 13 | Go to Step 9 |
7 | Test for an open or high resistance in the control circuit of the auto park lamp control relay. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 13 | Go to Step 9 |
8 | Inspect for poor connections at the auto park lamp control relay. 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 13 | Go to Step 11 |
9 | Inspect for poor connections at the harness connector of the body control module (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 13 | Go to Step 12 |
10 | Repair an open, high resistance, or short to ground in the coil side battery positive voltage circuit of the auto park lamp control relay. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 13 | -- |
11 | Replace the ALC park lamp relay. Did you complete the replacement? | Go to Step 13 | -- |
12 | Replace the BCM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement? | Go to Step 13 | -- |
13 |
Does the DTC reset? | Go to Step 2 | System OK |
