Diagnostics in this manual assume a certain skill level and knowledge of Ford-specific diagnostic practices.
REFER to: Diagnostic Methods (100-00 General Information, Description and Operation).
DTC Chart: BCM
BCM DTC Chart
DTC | Description | Action |
---|---|---|
B1A85:21 | Ambient Light Sensor: Signal Amplitude < Minimum | GO to Pinpoint Test B |
B1A85:22 | Ambient Light Sensor: Signal Amplitude > Maximum | GO to Pinpoint Test B |
Symptom Chart(s)
Diagnostics in this manual assume a certain skill level and knowledge of Ford-specific diagnostic practices.
REFER to: Diagnostic Methods (100-00 General Information, Description and Operation).
Symptom Chart: Autolamps
Symptom Chart
Condition | Possible Sources | Actions |
---|---|---|
A module does not respond to the diagnostic scan tool |
|
REFER to: Communications Network (418-00 Module Communications Network, Diagnosis and Testing). |
The autolamps are inoperative | Refer to the Pinpoint Test | GO to Pinpoint Test A |
The autolamps are on continuously | Refer to the Pinpoint Test | GO to Pinpoint Test B |
Pinpoint Tests
The Autolamps Are Inoperative
Refer to Wiring Diagrams Cell 71 for schematic and connector information.
Normal Operation and Fault Conditions
REFER to: Exterior Lighting - System Operation and Component Description (417-01 Exterior Lighting, Description and Operation).
Possible Sources
A1 CHECK FOR VOLTAGE TO THE LIGHT SENSOR | ||||||||||||||||
Is the voltage approximately 5 volts?
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A2 CHECK FOR CORRECT BCM (BODY CONTROL MODULE) OPERATION | ||||||||||||||||
Is the concern still present?
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The Autolamps Are On Continuously
Refer to Wiring Diagrams Cell 71 for schematic and connector information.
Normal Operation and Fault Conditions
REFER to: Exterior Lighting - System Operation and Component Description (417-01 Exterior Lighting, Description and Operation).
DTC Fault Trigger Conditions
DTC | Description | Fault Trigger Conditions |
---|---|---|
B1A85:21 | Ambient Light Sensor: Signal Amplitude < Minimum | A continuous memory DTC that sets when the BCM detects a short to ground from the light sensor input circuit. |
B1A85:22 | Ambient Light Sensor: Signal Amplitude > Maximum | A continuous memory DTC that sets when the BCM detects an open or short to voltage from the light sensor input circuit. |
Possible Sources
Visual Inspection and Diagnostic Pre-checks
B1 CHECK FOR BCM (BODY CONTROL MODULE) DIAGNOSTIC TROUBLE CODE (DTCS) | ||||||||||||||||
Is DTC B1A85:21 or B1A85:22 present?
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B2 CHECK FOR VOLTAGE TO THE LIGHT SENSOR (NO DTC (DIAGNOSTIC TROUBLE CODE) ) | ||||||||||||||||
Is the voltage approximately 5 volts?
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B3 CHECK FOR VOLTAGE TO THE LIGHT SENSOR (DTC (DIAGNOSTIC TROUBLE CODE) B1A85:21) | ||||||||||||||||
Is the voltage approximately 5 volts?
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B4 CHECK THE LIGHT SENSOR INPUT CIRCUIT FOR A SHORT TO GROUND | ||||||||||||||||
Is the resistance greater than 10,000 ohms?
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B5 CHECK FOR VOLTAGE TO THE LIGHT SENSOR (DTC (DIAGNOSTIC TROUBLE CODE) B1A85:22) | ||||||||||||||||
Is the voltage approximately 5 volts?
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B6 CHECK THE LIGHT SENSOR | ||||||||||||||||
Is the voltage approximately 5 volts?
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B7 CHECK THE LIGHT SENSOR GROUND CIRCUIT FOR AN OPEN | ||||||||||||||||
Is the resistance less than 3 ohms?
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B8 CHECK THE LIGHT SENSOR INPUT CIRCUIT FOR A SHORT TO VOLTAGE | ||||||||||||||||
Is any voltage present?
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B9 CHECK THE LIGHT SENSOR INPUT CIRCUIT FOR AN OPEN | ||||||||||||||||
Is the resistance less than 3 ohms?
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B10 CHECK FOR CORRECT BCM (BODY CONTROL MODULE) OPERATION | ||||||||||||||||
Is the concern still present?
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Removal
NOTE: Removal steps in this procedure may contain installation details.
Remove the brake shoes.