Pinpoint Test A: One Or Both Low Beams Is Inoperative Or Always On - Halogen Headlamps
- Refer to Wiring Diagrams Headlamps/Autolamps
for schematic and connector information.
Normal Operation and Fault Conditions
REFER to: Exterior Lighting - Overview . REFER to: Exterior Lighting - System Operation and Component Description .
DTC Fault Trigger Conditions
DTC Description Fault Trigger Condition BCM B14E0:11 Exterior Lamps Power Supply "C": Circuit Short To Ground A continuous memory and on-demand DTC that sets when the BCM detects a short to ground from the LH low beam output circuit. BCM B14E0:15 Exterior Lamps Power Supply "C": Circuit Short To Battery Or Open A continuous memory and on-demand DTC that sets when the BCM detects an open from the LH low beam output circuit. BCM B14E1:11 Exterior Lamps Power Supply "D": Circuit Short To Ground A continuous memory and on-demand DTC that sets when the BCM detects a short to ground from the RH low beam output circuit. BCM B14E1:15 Exterior Lamps Power Supply "D": Circuit Short To Battery Or Open A continuous memory and on-demand DTC that sets when the BCM detects an open from the RH low beam output circuit. BCM B1533:02 Headlamp Switch Module: General Signal Failure A continuous memory and on-demand DTC that sets when the BCM is missing data from the messages sent from the headlamp switch over the LIN circuit. BCM B1533:08 Headlamp Switch Module: Bus Signal/Message Failures A continuous memory and on-demand DTC that sets when the BCM has lost communication with the headlamp switch over the LIN circuit. BCM B1533:49 Headlamp Switch Module: Internal Electronic Failure A continuous memory and on-demand DTC that sets when the BCM message from the headlamp switch over the LIN circuit the headlamps switch has an internal failure. BCM B1533:56 Headlamp Switch Module: Invalid/Incompatible Configuration A continuous memory and on-demand DTC that sets when the BCM, over the LIN circuit, has detected that the headlamp switch is not properly configured. BCM B1D00:11 Left Low Beam: Circuit Short To Ground A continuous memory and on-demand DTC that sets when the BCM detects a short to ground from the LH low beam output circuit. BCM B1D00:15 Left Low Beam: Circuit Short To Battery Or Open A continuous memory and on-demand DTC that sets when the BCM detects an open from the LH low beam output circuit. BCM B1D01:11 Right Low Beam: Circuit Short To Ground A continuous memory and on-demand DTC that sets when the BCM detects a short to ground from the RH low beam output circuit. BCM B1D01:15 Right Low Beam: Circuit Short To Battery Or Open A continuous memory and on-demand DTC that sets when the BCM detects an open from the RH low beam output circuit. Possible Sources
- Wiring, terminals or connectors
- Bulb
- BCM
Visual Inspection and Pre-checks
- Inspect the headlamp assembly for damage.
- A1 CHECK LOW BEAMS OPERATION
- Ignition ON.
- Place the headlamp switch in the OFF position.
- Observe the operation of the LH and RH low beam.
- Place the headlamp switch in the HEADLAMPS position.
- Observe the operation of the LH and RH low beam.
Are either of low beams always illuminated?
Yes GO to A2 No GO to A10 - A2 DETERMINE IF BOTH LOW BEAMS ARE ALWAYS ON
- Place the headlamp switch in the OFF position.
- Observe the operation of the LH and RH low beam.
Are both low beams illuminated?
Yes GO to A3 No GO to A9 - A3 CHECK FOR BCM (BODY CONTROL MODULE) DIAGNOSTIC TROUBLE CODES (DTCS)
- Ignition ON.
- Using a diagnostic scan tool, perform the BCM self-test.
Is DTC B1533:02, B1533:08, B1533:49 or B1533:56 present?
Yes For BCMDTC B1533:02 or B1533:08, GO to A4 For BCMDTC B1533:49, INSTALL a new headlamp switch. REFER to: Headlamp Switch . For BCMDTC B1533:56, using the diagnostic scan tool, execute the BCMLIN New Module Initialization routine. Follow the diagnostic scan tool directions. If the initialization routine fails, INSTALL a new headlamp switch. REFER to: Headlamp Switch . No GO to A9 - A4 CHECK THE HEADLAMP SWITCH VOLTAGE SUPPLY CIRCUIT FOR AN OPEN
- Ignition OFF.
- Disconnect: Headlamp Switch C205.
- Ignition ON.
- Measure:
Positive Lead Measurement / Action Negative Lead C205-8 Ground
Is the voltage greater than 11 volts?
Yes GO to A5 No VERIFY the BCM fuse 19 (5A) is OK. If OK, REPAIR the circuit. If not OK, REFER to the OEM ELECTRICAL WIRING DIAGRAM INTRODUCTION to identify the possible causes of the circuit short. - A5 CHECK THE HEADLAMP SWITCH GROUND CIRCUIT FOR AN OPEN
Is the voltage greater than 11 volts?
Yes GO to A6 No REPAIR the circuit. - A6 CHECK THE LIN (LOCAL INTERCONNECT NETWORK) CIRCUIT TO THE HEADLAMP SWITCH FOR AN OPEN
- Ignition OFF.
- Disconnect: BCM C2280B.
Is the resistance less than 3 ohms?
Yes GO to A7 No REPAIR the circuit. - A7 CHECK THE LIN (LOCAL INTERCONNECT NETWORK) CIRCUIT FOR A SHORT TO VOLTAGE
- Ignition ON.
- Measure:
Positive Lead Measurement / Action Negative Lead C2280B-49 Ground
Is any voltage present?
Yes REMOVE the fused jumper wire. REPAIR the circuit. No REMOVE the fused jumper wire. GO to A8 - A8 CHECK THE LIN (LOCAL INTERCONNECT NETWORK) CIRCUIT FOR A SHORT TO GROUND
- Ignition OFF.
- Measure:
Positive Lead Measurement / Action Negative Lead C2280B-49 Ground
Is the resistance greater than 10, 000 ohms?
Yes INSTALL a new headlamp switch. REFER to: Headlamp Switch . TEST the system for normal operation. If the low beams continue to illuminate, GO to A9 No REPAIR the circuit. - A9 CHECK THE LOW BEAM CIRCUIT FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: BCM C2280G.
- Disconnect: LH Headlamp C1021 or RH Headlamp C1041.
- Ignition ON.
- Measure:
LH Headlamp
Positive Lead Measurement / Action Negative Lead C1021-1 Ground RH Headlamp
Positive Lead Measurement / Action Negative Lead C1041-1 Ground
Is any voltage present?
Yes REPAIR the circuit. No GO to A16 - A10 DETERMINE IF ONE OR BOTH LOW BEAMS ARE INOPERATIVE
- Ignition ON.
- Place the headlamp switch in the HEADLAMPS position.
Are both low beams inoperative?
Yes GO to A16 No GO to A11 - A11 CHECK FOR VOLTAGE FROM THE HEADLAMP LOW BEAM CIRCUIT
- Place the headlamp switch in the OFF position.
- Ignition OFF.
- Disconnect: LH Headlamp C1021 or RH Headlamp C1041.
- Ignition ON.
- Place the headlamp switch in the HEADLAMPS position.
- Measure:
LH Headlamp
Positive Lead Measurement / Action Negative Lead C1021-1 Ground RH Headlamp
Positive Lead Measurement / Action Negative Lead C1041-1 Ground
Is the voltage greater than 11 volts?
Yes GO to A15 No GO to A12 - A12 REPEAT THE ON-DEMAND SELF-TEST AND CHECK FOR VOLTAGE HEADLAMP LOW BEAM CIRCUIT
- Place the headlamp switch in the OFF position.
- Using a diagnostic scan tool, perform the BCM self-test.
- Clear the Diagnostic Trouble Codes (DTCs) and repeat the self-test (required to enable the lamp output driver).
- Ignition OFF.
- Ignition ON.
- Place the headlamp switch in the HEADLAMPS position.
- Measure:
LH Headlamp
Positive Lead Measurement / Action Negative Lead C1021-1 Ground RH Headlamp
Positive Lead Measurement / Action Negative Lead C1041-1 Ground
Is the voltage greater than 11 volts?
Yes INSTALL a new low beam headlamp bulb. REFER to: Headlamp Bulb . No GO to A13 - A13 CHECK THE LOW BEAM CIRCUIT FOR A SHORT TO GROUND
- Ignition OFF.
- Place the headlamp switch in the OFF position.
- Disconnect: BCM C2280G.
- Measure:
LH Headlamp
Positive Lead Measurement / Action Negative Lead C1021-1 Ground RH Headlamp
Positive Lead Measurement / Action Negative Lead C1041-1 Ground
Is the resistance greater than 10, 000 ohms?
Yes GO to A14 No REPAIR the circuit. After the repair: If no Diagnostic Trouble Codes (DTCs) are present, TEST the system for normal operation. If any BCM Diagnostic Trouble Codes (DTCs) other than DTC U3000:49 are present, CLEAR the Diagnostic Trouble Codes (DTCs), REPEAT the self-test (required to enable the lamp output driver) and cycle the ignition OFF and ON. TEST the system for normal operation. If DTC U3000:49 is present, INSTALL a new BCM. REFER to: Body Control Module (BCM) . - A14 CHECK THE LOW BEAM CIRCUIT FOR AN OPEN
- Measure:
LH Headlamp
Positive Lead Measurement / Action Negative Lead C1021-1 C2280G-4 RH Headlamp
Positive Lead Measurement / Action Negative Lead C1041-1 C2280G-2
Is the resistance less than 3 ohms?
Yes GO to A16 No REPAIR the circuit. - Measure:
- A15 CHECK THE HEADLAMP GROUND CIRCUIT FOR AN OPEN
- Measure:
LH Headlamp
Positive Lead Measurement / Action Negative Lead C1021-1 C1021-3 RH Headlamp
Positive Lead Measurement / Action Negative Lead C1041-1 C1041-3
Is the voltage greater than 11 volts?
Yes For halogen headlamps, INSTALL a new low beam headlamp bulb. REFER to: Headlamp Bulb . No REPAIR the circuit in question. - Measure:
- A16 CHECK FOR CORRECT BCM (BODY CONTROL MODULE) OPERATION
- Disconnect and inspect all BCM and all related in-line connectors.
- Repair:
- corrosion (install new connector or terminals - clean module pins)
- damaged or bent pins - install new terminals/pins
- pushed-out pins - install new pins as necessary
- Reconnect the BCM and all related in-line connectors. Make sure they seat and latch correctly.
- Operate the system and determine if the concern is still present.
Is the concern still present?
Yes CHECK OASIS for any applicable service articles: TSB, GSB, SSM or FSA. If a service article exists for this concern, DISCONTINUE this test and FOLLOW the service article instructions. If no service articles address this concern, INSTALL a new BCM. REFER to: Body Control Module (BCM) . No The system is operating correctly at this time. The concern may have been caused by module connections. ADDRESS the root cause of any connector or pin issues.