Circuit Description
The BCM provides control for the LH DRL relay circuit. The BCM grounds CKT 1976 in order to energize the LH DRL relay and turn ON the LF turn signal This allows the LF turn signal to be used for DRL, UTD, and approach lighting functions. The BCM monitors the voltage level on CKT 1976. When the BCM commands the relay ON, the voltage level on CKT 1976 should be low. When the relay is OFF, the voltage on CKT 1976 should be high. If the BCM detects a voltage level other than expected, a malfunction is present and a DTC will set.
Conditions for Setting the DTC
| • | The BCM detects a low voltage level (an open or a short to ground) in CKT 1976. |
| • | The BCM can only test for this condition with the LH DRL relay de-energized. |
| • | This condition must be present for 2 seconds. |
Action Taken When the DTC Sets
| • | Stores a DTC B0507 in the BCM memory. |
| • | No driver warning message will be displayed for this DTC. |
Conditions for Clearing the DTC
| • | This DTC requires an ignition cycle in order to change from current to history. |
| • | The BCM no longer detects a low voltage level in CKT 1976 only with the LH DRL relay de-energized. |
| • | 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 or short to ground in CKT 1976. |
| - | There is high resistance in the relay coil. |
| - | There are poor connections at the BCM, the I/P electrical center, or the LH DRL relay terminals. |
| - | The LH DRL relay is shorted or open internally. |
| • | If CKT 1976 is shorted to ground, the LH DRL will remain ON at all times and LH turn signal will not flash. If CKT 1976 is open, the LH DRL will remain OFF at all times, but the LH turn signal will still function normally. |
| • | 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. Refer to Intermittents and Poor Connections Diagnosis . |
Test Description
The numbers below refer to the step numbers on the diagnostic table:
-
This test determines if there is an open in the I/P electrical center or fuse.
-
This test checks the LH DRL relay control circuit by using a scan tool to command the BCM to energize the LH DRL relay ON and OFF.
-
This test determines if there is an open or short to ground in CKT 1976.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Were you sent here from the BCM Diagnostic System Check? | -- | ||
Is the test light ON? | -- | |||
Does the test light turn ON and OFF with each command? | -- | |||
Check for an open or short to ground in CKT 1976. Was a problem found and repaired? | -- | |||
5 | Check for poor connections at the LH DRL relay. Was a problem found and repaired? | -- | ||
6 | Check for poor connections at the harness connector of the body control module. Was a problem found and repaired? | -- | ||
7 |
Is the circuit repair complete? | -- | -- | |
8 | Replace the LH DRL relay. Is the replacement complete? | -- | -- | |
9 |
Is the replacement complete? | -- | -- | |
10 |
Is the repair complete? | -- | -- |
