B1894 – Wiper Rear Motor Speed Sense Circuit Failure

The ODBII code B1894 indicates a failure in the rear wiper motor speed sense circuit, which means there is a problem with the signal that monitors the speed of the rear wiper motor.

The severity of ODBII code B1894 is generally considered moderate.

Common Causes For: B1893 GPS Antenna Open Circuit

• Faulty rear wiper motor
• Damaged wiring or connectors
• Poor ground connection
• Failed wiper motor speed sensor
• Corroded terminals
• Short circuit in the circuit
• Open circuit in the wiring harness
• Malfunctioning body control module (BCM)

Common misdiagnosis for B1894 Wiper Rear Motor Speed Sense Circuit Failure

• Faulty rear wiper motor
• Bad wiring or connectors
• Malfunctioning body control module (BCM)
• Incorrectly diagnosed windshield wiper switch
• Issues with the front wiper system
• Battery or charging system problems
• Faulty ground connections

Common Troubleshooting Steps

The OBD-II code B1894 indicates a “Wiper Rear Motor Speed Sense Circuit Failure.” This code typically relates to issues with the rear wiper motor or its associated circuitry. Here are some common troubleshooting steps to diagnose and potentially resolve the issue:

• Check the Vehicle’s Manual: Refer to the vehicle’s service manual for specific information regarding the rear wiper motor and the associated wiring diagrams.
• Visual Inspection: Inspect the rear wiper motor and its wiring harness for any visible damage, corrosion, or loose connections.
• Check the connectors for signs of wear or damage.
• Test the Rear Wiper Motor: Use a multimeter to test the rear wiper motor for proper operation. You can apply direct power to the motor to see if it functions correctly.
• If the motor does not operate when powered directly, it may need to be replaced.
• Check the Speed Sense Circuit: Inspect the speed sense circuit for continuity. Use a multimeter to check for any breaks or shorts in the wiring.
• Ensure that the circuit is not grounded or shorted to another circuit.
• Examine the Wiper Control Module: If applicable, check the wiper control module for faults. This module may be responsible for sending signals to the rear wiper motor.
• Test the module for proper operation and replace it if necessary.
• Scan for Additional Codes: Use an OBD-II scanner to check for any additional trouble codes that may provide more context or indicate related issues.
• Inspect the Fuse: Check the fuse associated with the rear wiper motor. If the fuse is blown, replace it and see if the issue persists.
• Check for Ground Issues: Ensure that the rear wiper motor has a good ground connection. A poor ground can lead to erratic behavior or failure.
• Clear the Code: After performing repairs or replacements, clear the trouble code using an OBD-II scanner and take the vehicle for a test drive to see if the code returns.
• Consult a Professional: If the issue persists after performing these steps, it may be best to consult a professional mechanic or technician who has experience with your specific vehicle model. By following these troubleshooting steps, you should be able to identify and resolve the issue related to the B1894 code.