DTC B0984 or B0985
Diagnostic Instructions
DTC Descriptors
| DTC B0984 00: Left Headlamp Light Distribution
Shutter Control Circuit Malfunction |
| DTC B0985 00: Right Headlamp Light
Distribution Shutter Control Circuit Malfunction |
Diagnostic Fault Information
Circuit
|
Short to Ground
|
Open/High Resistance
|
Short to Voltage
|
Signal Performance
|
Headlamp Motor B+
|
1
|
1
|
-
|
-
|
Headlamp Motor Module Control
|
1
|
1
|
1
|
B0984 00, B0985 00*
|
Headlamp Control Module Control
|
1
|
1
|
1
|
1
|
Headlamp Motor Ground
|
-
|
1
|
-
|
-
|
* Headlamp leveling motor malfunction or overtemperature
1. Headlamp leveling malfunction
|
|
| |
Circuit/System Description
Battery positive voltage is applied to the headlamp control
module at all times. The headlamp control module has a normal
operational voltage range of about 12.5-16 V and is only fully
functional with the ignition switch is in the RUN position and the
headlamp switch in the AUTO position. The communications enable
signal from the body control module (BCM) wakes the headlamp
control module microprocessor. The headlamp control module receives
serial data messages from the engine control module (ECM),
transmission control module (TCM), electronic brake control module
(EBCM), and BCM with information regarding power mode, speed,
steering angle, transmission gear selection, and headlamp switch
status. The headlamp control module calculates the headlamp angle
and sends commands to the left and right adaptive forward lighting
system headlamp actuators. The headlamp actuators drive the
headlamps to the position commanded by the headlamp control module.
The headlamp control module monitors the headlamp actuator motor
control circuits for proper circuit continuity and for shorts to
ground or voltage. If a malfunction is detected, a DTC will be
stored in memory and the driver will be notified with a message
displayed over the driver information center located on the
instrument cluster.
Conditions for Running the DTC
| • |
Battery voltage must be
between 9-16 V. |
| • |
The ignition is in the ON or
RUN position. |
Conditions for Setting the DTC
B0984 00 or B0985 00
The DTC will set when the headlamp control module detects no signal
and low voltage on the sensor signal line.
Action Taken When the DTC Sets
| • |
The headlamp control module
disables the headlamp leveling system. |
| • |
Headlamp leveling inoperative
indication ON. |
| • |
Advanced front lighting system
fault indication ON. |
Conditions for Clearing the DTC
The condition responsible for setting the DTC no longer
exists.
Reference Information
Schematic Reference
Headlights/Daytime Running Lights (DRL) Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Exterior Lighting Systems Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
Verify that DTC B3415 is not present.
If DTC is present, refer to
DTC B3415 .
Circuit/System Testing
| 1. |
Ignition OFF, disconnect the
harness connector at the appropriate headlamp assembly.
|
| 2. |
Test for less than 5 Ω
between the ground circuit terminal 1, 8 and ground. |
| ⇒ |
If greater than the specified range, test the
ground circuit for an open/high resistance. |
| 3. |
Ignition ON, connect a test
lamp between the ignition circuit terminal 6 and ground. The test
lamp should illuminate. |
| ⇒ |
If the test lamp does not illuminate, test the
ignition circuit for a short to ground or an open/high
resistance. |
| 4. |
If all circuits test normal,
replace the appropriate headlamp assembly. Verify that the DTC do
not reset. |
| ⇒ |
If the DTC resets, replace the K28 Headlamp
Leveling Control Module. |
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic
procedure.
|
