Inspection and Verification

Visually inspect the following for obvious signs of mechanical or electrical damage.

VISUAL INSPECTION CHART

Mechanical	Electrical
Headlamp switch	Bussed electrical center (BEC) fuse(s): 45 (15A) (high beam headlamps) 62 (30A) (RH low beam) 65 (30A) (LH low beam) Circuitry Smart junction box (SJB) Bulbs

If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to the next step.

NOTE: Make sure the headlamp switch is in the OFF position.

NOTE: Make sure the multifunction switch is in the LOW BEAM position.

NOTE: Make sure to use the latest scan tool software release.

If the cause is not visually evident, connect the scan tool to the data link connector (DLC).

NOTE: The vehicle communication module (VCM) LED prove-out confirms power and ground from the DLC are provided to the VCM.

If the scan tool does not communicate with the VCM:
- Check the VCM connection to the vehicle.
- Check the scan tool connection to the VCM.
- Refer to MODULE COMMUNICATIONS NETWORK article, No Power To The Scan Tool, to diagnose no communication with the scan tool.
If the scan tool does not communicate with the vehicle:
- Verify the ignition key is in the ON position.
- Verify the scan tool operation with a known good vehicle.
- Refer to MODULE COMMUNICATIONS NETWORK article to diagnose no response from the powertrain control module (PCM).
Carry out the network test.
- If the scan tool responds with no communication for one or more modules, refer to MODULE COMMUNICATIONS NETWORK article.
- If the network test passes, retrieve and record the continuous memory diagnostic trouble codes (DTCs).
Clear the continuous DTCs and carry out the self-test diagnostics for the SJB.
If the DTCs retrieved are related to the concern, go to the Smart Junction Box (SJB) Diagnostic Trouble Code (DTC) Index. For all other DTCs, refer to MULTIFUNCTION ELECTRONIC MODULES article.
If no DTCs related to the concern are retrieved, go to Symptom Chart .

SMART JUNCTION BOX (SJB) DIAGNOSTIC TROUBLE CODE (DTC) INDEX

DTC	Description	Action
B1342	ECU is Defective	CLEAR the DTCs. RETRIEVE the DTCs. If DTC B1342 is retrieved, INSTALL a new SJB. REFER to MULTIFUNCTION ELECTRONIC MODULES article. TEST the system for normal operation.
B2501	LF Low Beam Circuit Failure	If the low beam is inoperative, go to Pinpoint Test B . If the low beam is always on, go to Pinpoint Test C .
B2503	RF Low Beam Circuit Failure	If the low beam is inoperative, go to Pinpoint Test B . If the low beam is always on, go to Pinpoint Test C .
B2586	Headlamp Mode Select Circuit Failure	Go to Pinpoint Test A .
B2598	Headlamp Relay Circuit Failure	If the high beams are inoperative, go to Pinpoint Test A . If the high beams are always on, go to Pinpoint Test C .
All other DTCs	-	REFER to MULTIFUNCTION ELECTRONIC MODULES article.