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, a short to ground, a poor connection, or an open in the park lamp relay control circuit when it is trying to energize the park lamp relay. |
| • | A short to ground in the park lamp supply voltage circuit |
| • | An open in the park lamp relay coil |
| • | The condition above must be present for more than 0.3 second. |
Action Taken When the DTC Sets
The park lamps will not operate or will remain always ON.
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 a current code. |
| • | A short to ground in the park lamp supply voltage 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 a current code. |
| • | A history DTC will clear after 100 consecutive ignition cycles if the condition for the malfunction is no longer present. |
| • | Current and history DTCs can be cleared using 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 .
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 Testing for Intermittent Conditions and Poor Connections | 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 11 | Go to Step 8 |
5 | Turn the headlamp switch to the PARK position. Does the test lamp illuminate? | Go to Step 9 | 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 11 | Go to Step 7 |
7 | Test for a short to ground in the park lamp voltage supply circuit. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 11 | Go to Step 8 |
8 | 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 . Did you find and correct the condition? | Go to Step 11 | Go to Step 10 |
9 | Replace the park lamp relay. Refer to Relay Replacement . Did you complete the replacement? | Go to Step 11 | -- |
10 | Replace the BCM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | Go to Step 11 | -- |
11 |
Does the DTC reset? | Go to Step 2 | System OK |
