Diagnostic Aids

WARNING: This page is about a different car, the 2006 Buick LaCrosse and 2006 Buick Allure. However, it is still accessible from the selected car via links, so may be relevant.

If the DTC B3838 is a history DTC, the fault may be intermittent. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
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.

DTC B3838

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
2	Install a scan tool. Turn ON the ignition, with the engine OFF. With a scan tool, command the PK LP relay ON and OFF. Does the PK LP relay turn ON and OFF with each command?	Go to Diagnostic Aids	Go to Step 3
3	The PK LP relay is located on the back side of the I/P fuse block. Turn OFF the ignition. Disconnect the PK LP relay. Turn ON the ignition, with the engine OFF. Turn the headlamp switch to the OFF position. Connect a test lamp between the control circuit of the park lamp relay and the coil side supply circuit of the park lamp relay. 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 in Wiring Systems. 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 voltage, an open or a poor connection in the park lamp relay control circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. 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 in Wiring Systems. Did you find and correct the condition?	Go to Step 10	Go to Step 8
8	Replace the PK LP relay. Refer to Relay Replacement (Within an Electrical Center) or Relay Replacement (Attached to Wire Harness) in Wiring Systems. Did you complete the replacement?	Go to Step 10	-
9	Replace the body control module (BCM). Refer to Control Module References in Computer/Integrating Systems for replacement, setup and programming. Did you complete the replacement?	Go to Step 10	-
10	Use the scan tool in order to clear the DTCs. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text. Does the DTC reset?	Go to Step 2	System OK