DTC B371A
Diagnostic Instructions
DTC Descriptor
DTC B371A 39: Windscreen Wiper Motor
Internal Malfunction
Circuit/System Description
B+ voltage and ground are supplied to the windscreen wiper
motor. Whenever the ignition is ON, or in accessory positions, the
body control module (BCM), sends the wiper/washer switch status
through the LIN communication bus. If a fault occurs at any time in
the windscreen wiper motor, the BCM will set this DTC.
Conditions for Running the DTC
The module runs the program to detect an internal fault when
power up is commanded. The only requirements are voltage and
ground. This program runs even if the voltage is out of the valid
operating range.
Conditions for Setting the DTC
The BCM receives an invalid signal from the windscreen wiper
motor.
Action Taken When the DTC Sets
The module refuses all additional inputs.
Conditions for Clearing the DTC
A current DTC clears when the diagnostic runs and passes.
Diagnostic Aids
Diagnose any communication DTCs (U-Codes) before attempting any
diagnosis.
Reference Information
Schematic Reference
Wiper/Washer Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Wiper/Washer System Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Testing
Left Hand Drive
- Ignition OFF, Retained Accessory Power OFF, disconnect
the harness connector at the M75 Windscreen Wiper Motor.
- Test for less than 5 Ω between the ground circuit
terminal 2 and ground.
⇒ |
If greater than the specified value, test the
ground circuit for an open/high resistance. |
- Ignition ON, verify that a test lamp illuminates
between B+ voltage circuit terminal 1 and ground.
⇒ |
If the test lamp does not illuminate, test the B+
voltage circuit for a short to ground or an open/high
resistance. |
- Ignition ON, test for 4-12 V between the
communication signal circuit terminal 4 and ground.
⇒ |
If not the specified range, test the signal
circuit for an open/high resistance and a short to voltage. If the
circuit tests normal, replace the K9 Body Control Module. |
- If all circuits test normal, replace the
M75 Windscreen Wiper Motor.
Right Hand Drive
- Ignition OFF, Retained Accessory Power OFF, disconnect
the harness connector at the M75 Windscreen Wiper Motor.
- Test for less than 5 Ω between the ground circuit
terminal 3 and ground.
⇒ |
If greater than the specified value, test the
ground circuit for an open/high resistance. |
- Ignition ON, verify that a test lamp illuminates
between B+ voltage circuit terminal 4 and ground.
⇒ |
If the test lamp does not illuminate, test the B+
voltage circuit for a short to ground or an open/high
resistance. |
- Ignition ON, test for 4-12 V between the
communication signal circuit terminal 1 and ground.
⇒ |
If not the specified range, test the signal
circuit for an open/high resistance and a short to voltage. If the
circuit tests normal, replace the K9 Body Control Module. |
- If all circuits test normal, replace the
M75 Windscreen Wiper Motor.
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic
procedure.
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