Headlamp Leveling Malfunction (RPO TT6, TT7 or TT8)
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Headlamp Leveling Malfunction (RPO TT6, TT7 or TT8)
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Diagnostic Fault Information
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Circuit
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Short to Ground
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Open/High Resistance
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Short to Voltage
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Signal Performance
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Ignition Left Headlamp
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2
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2
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-
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B1461 00
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Ignition Right Headlamp
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3
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3
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-
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B1462 00
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Headlamp Leveling Sensor 5V Reference - Front
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B3415 02
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1
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B3415 01
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-
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Headlamp Leveling Sensor 5V Reference - Rear
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B3415 02
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1
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B3415 01
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-
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Headlamp Leveling Sensor Signal - Front
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B3410 06
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B3410 06
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B3410 01
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-
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Headlamp Leveling Sensor Signal - Rear
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B3420 06
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B3420 06
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B3420 01
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-
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Headlamp Leveling Sensor Low Reference - Front
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-
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1
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-
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-
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Headlamp Leveling Sensor Low Reference - Rear
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-
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1
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-
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-
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Left Headlamp Ground
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-
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2
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-
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B1461 00
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Right Headlamp Ground
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-
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3
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-
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B1462 00
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1. All Headlamp Leveling Actuator Malfunction
2. Left Headlamp Leveling Actuator Malfunction
3. Right Headlamp Leveling Actuator Malfunction
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Circuit/System Description
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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 AUTOMATIC LIGHT 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.
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
Headlamp Leveling Sensor Malfunction
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1.
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Ignition OFF, disconnect the harness connector at the appropriate B51 headlamp leveling sensor.
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2.
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Test for less than 5 Ω between the low reference circuit terminal 3 and ground.
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3.
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If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the K28 headlamp leveling control module.
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4.
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Ignition ON, test for 4.8-5.2 V between the 5V reference circuit terminal 1 and ground.
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5.
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If less than the specified range, test the 5V reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K28 headlamp leveling control module.
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6.
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If greater than the specified range, test the 5V reference circuit for a short to voltage. If the circuit tests normal, replace the K28 headlamp leveling control module.
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7.
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Verify the appropriate scan tool Leveling Position Sensor parameter is 0 V.
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8.
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If greater than the specified range, test the signal circuit pin 2 for a short to voltage. If the circuit tests normal, replace the K28 headlamp leveling control module.
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9.
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Install a 3 A fused jumper wire between the signal circuit terminal 2 and the 5V reference circuit terminal 1. Verify the appropriate scan tool Leveling Position Sensor parameter is greater than 5 V.
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10.
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If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K28 headlamp leveling control module.
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11.
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If all circuits test normal, replace the B51 headlamp leveling sensor.
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Headlamp Leveling Actuator Malfunction
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1.
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Ignition OFF, disconnect the inline harness connector listed below:
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•
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M29L headlamp leveling actuator-left inline harness connector X111
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•
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M29R headlamp leveling actuator-right inline harness connector X112
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2.
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Test for less than 30 Ω between the ground circuit terminal A and ground.
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3.
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If greater than the specified range, test the ground circuit for an open/high resistance.
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4.
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Engine running, test for less than 30 Ω between the ground circuit terminal E and ground.
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5.
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If greater than the specified range, test the ground circuit for an open/high resistance. If the circuit tests normal, replace the K28 headlamp leveling control module.
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6.
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Verify that a test lamp illuminates between the control circuit terminal D and ground.
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7.
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If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K28 headlamp leveling control module.
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8.
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Test for 4.25 V-5.25 V between the signal circuit terminal M and ground.
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9.
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If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K28 headlamp leveling control module.
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10.
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If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the K28 headlamp leveling control module.
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11.
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If all circuits test normal, test or replace the M29 headlamp leveling actuator
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Perform the
Diagnostic Repair Verification
after completing the diagnostic procedure.
