Circuit Description
The body control module (BCM) controls the park lamp relay through the park lamp relay control circuit. The BCM grounds the park lamp relay control circuit which energizes the park lamp relay.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC B3838 Park Lamp Relay Control Circuit
Conditions for Running the DTC
The BCM must be commanding the park lamp relay to energize.
Conditions for Setting the DTC
| • | The BCM detects a short to battery positive voltage, short to ground, poor connection or an open in the park lamp relay control circuit when it is trying to energize the park lamp relay. |
| • | The BCM detects a short to ground in the switched park lamp voltage supply circuit. |
| • | The condition above must be present for more than 0.3 seconds. |
Action Taken When the DTC Sets
The BCM stores DTC B3838 in memory.
Conditions for Clearing the DTC
| • | A fault in the park lamp relay control circuit is no longer detected by the BCM when the park lamp relay is commanded to energize. After the fault is removed the ignition must be cycled to clear the code. |
| • | A short to ground in the switched park lamp voltage supply circuit is no longer detected by the BCM when the park lamp relay is commanded to energize. After the fault is removed the ignition must be cycled to clear the code. |
| • | A history DTC B3838 will clear after 100 consecutive ignition cycles if the condition for the malfunction is no longer present. |
| • | The BCM receives a clear code command from the scan tool. |
Diagnostic Aids
| • | If the DTC B3838 is a history DTC, the fault may be intermittent. Refer to Testing for Intermittent Conditions and Poor Connections . |
| • | The following conditions may cause an intermittent malfunction to occur: |
| - | An intermittent fault in the park lamp relay coil control circuit. |
| - | The park lamp relay coil is shorted to battery positive voltage. |
| - | The BCM is shorted to battery positive voltage. |
| - | An intermittent short to ground in the switched park lamp voltage supply circuit. |
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Exterior Lights Schematics Connector End View Reference: Master Electrical Component List | |||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | |
2 |
Does the park lamp relay turn ON and OFF with each command? | Go to Diagnostic Aids | Go to Step 3 |
3 |
Does the test lamp illuminate? | Go to Step 4 | Go to Step 5 |
4 | Test the control circuit of the park lamp relay for a short to ground. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 10 | Go to Step 9 |
5 | Turn the headlamp switch to the PARK position. Does the test lamp illuminate? | Go to Step 7 | Go to Step 6 |
6 | Test for a short to battery positive, an open or a poor connection in the park lamp relay control circuit. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 10 | Go to Step 9 |
7 | Test for a short to ground in the switched park lamp voltage supply circuit. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 10 | Go to Step 8 |
8 | Replace the park lamp relay. Refer to Relay Replacement . Did you complete the replacement? | Go to Step 10 | -- |
9 | Replace the body control module (BCM). Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | Go to Step 10 | -- |
10 |
Does the DTC reset? | Go to Step 2 | System OK |
