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Engine-Codes – Generic – B1894

B1894 Code - Wiper Rear Motor Speed Sense Circuit Failure

Quick Answer

The B1894 diagnostic trouble code (DTC) indicates a failure in the wiper rear motor speed sense circuit. Common causes include Faulty rear wiper motor speed sensor, Damaged wiring or connectors in the speed sense circuit, Corrosion or moisture intrusion in the circuit. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means
B1894 indicates Wiper Rear Motor Speed Sense Circuit Failure.
Common causes
Common causes include Faulty rear wiper motor speed sensor, Damaged wiring or connectors in the speed sense circuit, Corrosion or moisture intrusion in the circuit.
Severity
High - diagnose this code as soon as possible.
Can I drive?
Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
What is this?
Table of contents Created and updated by William Orellana on Sep 30, 2024
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Code B1894 Description

The B1894 diagnostic trouble code (DTC) indicates a failure in the wiper rear motor speed sense circuit. This means that the vehicle's onboard computer has detected a problem with the circuit responsible for monitoring the speed of the rear wiper motor. The rear wiper motor speed sensor plays a crucial role in ensuring that the rear wiper operates at the correct speed, providing optimal visibility for the driver in inclement weather conditions. When this circuit fails, it can lead to erratic rear wiper operation, reduced visibility, and potential safety hazards.

OBDII Code B1894 - Wiper Rear Motor Speed Sense Circuit Failure
B1894 Code - Wiper Rear Motor Speed Sense Circuit Failure

Common Causes of B1894

  1. Faulty rear wiper motor speed sensor.
  2. Damaged wiring or connectors in the speed sense circuit.
  3. Corrosion or moisture intrusion in the circuit.
  4. Defective rear wiper motor.
  5. Issues with the vehicle's onboard computer or control module.

Symptoms of B1894

  1. Rear wiper operates erratically or intermittently.
  2. Rear wiper does not respond to speed settings.
  3. Rear wiper operates at an incorrect speed.
  4. Rear wiper motor makes unusual noises during operation.

How to Fix B1894

  1. Begin by conducting a visual inspection of the rear wiper motor speed sense circuit, checking for any visible damage, corrosion, or loose connections.
  2. Test the rear wiper motor speed sensor using a multimeter to determine if it is functioning correctly.
  3. Inspect the wiring harness and connectors for any signs of damage or wear, repairing or replacing as necessary.
  4. If the rear wiper motor speed sensor is found to be faulty, replace it with a new sensor compatible with the vehicle's make and model.
  5. Clear the DTC from the vehicle's onboard computer using a diagnostic scanner to reset the system and ensure proper operation of the rear wiper motor.

Cost to Fix B1894

The typical repair costs for addressing a B1894 code related to a wiper rear motor speed sense circuit failure can vary depending on the specific vehicle make and model, as well as the extent of the issue. In general, the cost of parts for this repair can range from $50 to $200, while labor costs may range from $100 to $300. It's important to note that diagnostic time and labor rates at auto repair shops can vary significantly, so it's advisable to check with local shops for a more accurate estimate based on your location and vehicle type.

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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about B1894 Code

1. What are the common symptoms of OBDII code B1894 (Wiper Rear Motor Speed Sense Circuit Failure)?

The common symptoms of code B1894 include the rear wiper not working or operating at an abnormal speed.

2. What are the possible causes of OBDII code B1894?

Possible causes of code B1894 include a faulty rear wiper motor, damaged wiring or connectors in the rear wiper system, or a defective rear wiper speed sensor.

3. How can I diagnose OBDII code B1894?

Diagnosing code B1894 involves inspecting the rear wiper motor, checking the wiring and connectors for damage, and testing the rear wiper speed sensor using a multimeter or scan tool.

4. What are the repair options for OBDII code B1894?

Repair options for code B1894 may include replacing the rear wiper motor, repairing or replacing damaged wiring or connectors, or replacing the rear wiper speed sensor.

5. Can I drive my vehicle with OBDII code B1894?

It is generally safe to drive your vehicle with code B1894, but you should address the issue promptly to ensure proper functioning of the rear wiper system.

6. How much does it cost to repair OBDII code B1894?

The cost of repairing code B1894 can vary depending on the specific cause of the issue, but it may range from a few hundred to a few thousand dollars, including parts and labor.

7. Can I reset OBDII code B1894 without fixing the underlying issue?

Resetting the code without addressing the root cause will only temporarily clear the check engine light. The code is likely to reappear until the issue is resolved.

8. Is OBDII code B1894 a common problem in vehicles?

Code B1894 (Wiper Rear Motor Speed Sense Circuit Failure) is not as common as some other OBDII codes, but it can occur in vehicles with rear wiper systems.

9. Can extreme weather conditions cause OBDII code B1894 to trigger?

Extreme weather conditions, such as heavy rain, snow, or extreme temperatures, can potentially contribute to the triggering of code B1894 if they lead to damage in the rear wiper system components.

10. How long does it typically take to repair OBDII code B1894?

The repair time for code B1894 can vary depending on the complexity of the issue and the availability of parts. In general, it may take a few hours to a full day to diagnose and repair the problem.

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