Circuit Description
The BCM monitors the RF turn signal circuit in order to determine the status of the turn signal switch. If the BCM detects an oscillating voltage on the RH turn signal monitor circuit, the BCM interprets this as a RF turn signal ON request from the turn signal switch. The BCM will then de-energizetheRH DRL relay, which will disable the RF turn signal lamp (which is ON forthe DRL), this allows the RF turn signal to flash. If the BCM does not detectan oscillating voltage on the RH turn signal monitor circuit, the BCM interpretsthis as the RF turn signal being OFF. The BCM will then energize the RH DRLrelay and continue normal DRL operation. The BCM monitors the RH turn signalmonitor circuit and determines how long voltage is applied.If the voltageis applied for longer than expected, a malfunction is presentand a DTC willset.
Conditions for Setting the DTC
| • | The BCM detects continuous battery positive voltage on the RH turn signal monitor circuit. |
| • | The condition must be present for longer than 5 seconds. |
Action Taken When the DTC Sets
Stores a DTC B2578 in the BCM memory.
Conditions for Clearing the DTC
| • | This DTC requires an ignition cycle in order to change from current to history. |
| • | The BCM no longer detects continuous battery positive voltage on the RH turn signal monitor circuit for longer than 5 seconds. |
| • | 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. |
| • | The BCM receives the Clear Code command from the scan tool. |
Diagnostic Aids
| • | The following conditions may cause an intermittent malfunction: |
| - | There is an intermittent short to battery positive voltage in the RH turn signal monitor circuit. |
| - | The turn signal switch or the hazard switch is internally shorted or is sticking. |
| • | The BCM needs to detect voltage oscillations on the RH turn signal monitor circuit in order to de-energize the RH DRL relay. If the BCM detectscontinuous voltage on the RH turn signal monitor circuit, the BCM interpretsthis as a short to battery positive voltage. The BCM will continue with normal DRL operation, and the RF turn signal will remain inoperative. |
| • | If the DTC is a history DTC, the problem may be intermittent. Perform the tests shown while moving related wiring and connectors. This canoften cause the malfunction to occur. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems. |
Test Description
The number(s) below refer to the step number(s) on the diagnostic table.
-
Tests if a DTC B2583 is stored in the BCM. If both the RH and LH turn signal monitor DTCsare stored, test the hazard switch and related circuits for a short tovoltage.
-
Tests if the BCM is receiving oscillating voltage on the RH turn signal monitor circuit.If the test lamp is ON steady, the BCM will set a DTC B2578.
-
Tests if the BCM is receiving oscillating voltage on the RH turn signal monitor circuit.If the test lamp is ON steady, the BCM will set a DTC B2578.
-
Tests if the turn signal switch or related circuits are shorted to voltage.
-
Tests if the hazard switch or related circuits are shorted to voltage.
-
Tests if the instrument panel cluster turn signal indicator is shorted to voltage.
-
Tests if the body control module is shorted to voltage.
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Headlights/Daytime Running Lights (DRL) Schematics Connector End View Reference: Master Electrical Component List | |||
1 | Did you perform the Lighting System Diagnostic System Check? | Go to Step 2 | |
Does the scan tool display DTC B2583? | Go to Step 10 | Go to Step 3 | |
Does the test lamp turn ON and OFF with the RH turn signals? | Go to Step 13 | Go to Step 4 | |
Does the test lamp remain illuminated? | Go to Step 5 | ||
Disconnect the turn signal switch. Does the test lamp remain illuminated? | Go to Step 6 | Go to Step 9 | |
Disconnect the hazard switch. Does the test lamp remain illuminated? | Go to Step 7 | Go to Step 10 | |
Disconnect the instrument panel cluster. Does the test lamp remain illuminated? | Go to Step 8 | Go to Step 11 | |
Disconnect the body control module. Does the test lamp remain illuminated? | Go to Step 12 | Go to Step 14 | |
9 | Repair a short to battery positive voltage in the turn signal switch circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 15 | -- |
10 | Repair a short to battery positive voltage in the hazard switch circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 15 | -- |
11 | Repair a short to battery positive voltage in the instrument panel turn signal indicator circuit. Refer to Wiring Repairs in WiringSystems. Did you complete the repair? | Go to Step 15 | -- |
12 | Repair a short to battery positive voltage in the turn signal monitor circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 15 | -- |
13 | Replace the RH DRL relay. Refer to Relay Replacement in Wiring Systems. Did you complete the replacement? | Go to Step 15 | -- |
14 |
Important: Perform the BCM reprogram procedure. Refer to Body Control Module (BCM) Programming/RPO Configuration in Body Control System. Replace the BCM. Refer to Body Control Module Replacement in Body Control System. Did you complete the replacement? | Go to Step 15 | -- |
15 |
Does the DTC reset? | Go to Step 2 | System OK |
