Backup Lamps Malfunction (AT)
Diagnostic Instructions
Diagnostic Fault Information
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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Reverse Gear Signal
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1
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1
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1
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1, 2
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1. Reverse Gear Lamp Inoperative
2. Reverse Gear Lamp Always ON
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|
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Circuit/System Description
When the automatic transmission is placed in the reverse
position, the transmission control module (TCM) sends a serial data
message to the body control module (BCM). The message indicates
that the gear selector is in the reverse position. The BCM applies
battery voltage to the backup lamp. The backup lamp are permanently
grounded. Once the driver moves the gear selector out of the
reverse position, a message is sent by the TCM via serial data
requesting the BCM to remove battery voltage from the backup lamp
control circuit.
Reference Information
Schematic Reference
Exterior Lights 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
Ignition ON, perform the Backup Lamp Relay test. The backup lamp
should be ON/OFF.
Circuit/System Testing
Observe the parameter Tap Up/Down Switch when putting the gear
selector is in the reverse position. The parameter Tap Up/Down
Switch should display that reverse gear is engaged.
If the Tap Up/Down Switch parameter displays the corresponding
gear, replace the K9 Body Control Module. If the Tap Up/Down Switch
parameter does not displays the corresponding gear, refer to
Transmission Control Lever Malfunction .
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic
procedure.
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