The B1839 trouble code indicates a malfunction within the rear wiper motor circuit of a vehicle. This code signals an electrical issue preventing the rear wiper motor from functioning correctly, impacting rear visibility, especially during inclement weather. Addressing this promptly is crucial for safety and maintaining clear rear vision.
Understanding the B1839 Code: Wiper Rear Motor Circuit Failure
The B1839 diagnostic trouble code (DTC) signifies a problem within the electrical circuit responsible for powering and controlling the rear wiper motor. It means the vehicle's computer, typically the Body Control Module (BCM), has detected an abnormal electrical condition, such as an open circuit, short to ground, or excessive resistance in the rear wiper motor circuit. This issue prevents the rear wiper from operating as intended.
| Topic | Description | Possible Causes |
|---|---|---|
| Definition | B1839 refers to a fault within the rear wiper motor circuit, indicating an electrical problem affecting its operation. | Open circuit, short to ground, short to voltage, high resistance in the circuit. |
| Symptoms | Rear wiper not working, intermittent wiper operation, wiper stops mid-cycle, blown fuse associated with the rear wiper, warning light on the dashboard. | Corroded wiring, damaged motor, faulty wiper switch, defective BCM, wiring harness damage. |
| Possible Causes | Faulty rear wiper motor, damaged wiring or connectors, corroded connections, blown fuse, faulty rear wiper switch, malfunctioning Body Control Module (BCM). | Water intrusion, physical damage to wiring, age-related wear and tear, electrical surges. |
| Diagnostic Steps | Visual inspection of wiring and connectors, testing the rear wiper motor, checking the fuse, testing the rear wiper switch, using a multimeter to check for continuity and voltage, scanning the BCM for related codes. | Using a diagnostic scan tool, multimeter, wiring diagrams. |
| Common Repair Solutions | Replacing the rear wiper motor, repairing or replacing damaged wiring or connectors, cleaning corroded connections, replacing the blown fuse, replacing the rear wiper switch, reprogramming or replacing the BCM (in rare cases). | Splicing wires, replacing connectors, fuse replacement, motor replacement, BCM replacement (as a last resort). |
| Related Codes | B1838 (Rear Wiper Motor Relay Circuit Malfunction), other B codes related to body control module malfunctions, U codes related to communication errors. | These codes often indicate a more complex electrical issue affecting multiple vehicle systems. |
| Tools Required | Multimeter, diagnostic scan tool, wiring diagrams, screwdrivers, pliers, wire stripper/crimper, connector cleaner. | These tools are required for accurate diagnosis and efficient repair. |
| Safety Precautions | Disconnect the negative battery terminal before working on the electrical system, wear safety glasses, use caution when working with electrical components, refer to the vehicle's service manual for specific procedures. | Avoiding electrical shock, protecting your eyes, proper grounding. |
| Fuse Location | Typically located in the interior fuse box or the engine compartment fuse box. Refer to the vehicle's owner's manual for the exact location and amperage. | Understanding the fuse location is crucial for quick troubleshooting. |
| Wiring Diagram Importance | Essential for tracing the rear wiper motor circuit, identifying components, and verifying wiring connections. | Enables accurate diagnosis and prevents accidental damage to other electrical components. |
| BCM Involvement | The BCM controls the rear wiper motor's operation and monitors the circuit for faults. A malfunctioning BCM can cause the B1839 code. | The BCM may require reprogramming or replacement if it's the source of the problem. |
| Corrosion Issues | Corrosion on wiring and connectors can create resistance in the circuit, leading to the B1839 code. | Cleaning corroded connections with a wire brush and applying dielectric grease can often resolve the issue. |
| Motor Testing | Testing the rear wiper motor directly with a power source can help determine if the motor is faulty. | This can be done by disconnecting the motor and applying 12V directly to the motor terminals. |
| Switch Testing | Testing the rear wiper switch with a multimeter can verify its functionality. | Check for continuity in the different switch positions. |
| Intermittent Problems | Intermittent B1839 codes can be more difficult to diagnose. Careful inspection of wiring and connectors is crucial. | Look for loose connections, chafed wires, or signs of water intrusion. |
| DIY vs. Professional | Simple repairs like fuse replacement and cleaning corroded connections can be done DIY. More complex repairs like motor replacement or BCM diagnosis may require professional assistance. | Consider your skill level and available tools before attempting repairs. |
| Vehicle-Specific Information | The exact location of components and wiring diagrams may vary depending on the vehicle's make and model. | Always consult the vehicle's service manual for specific information. |
| Impact on Safety | A non-functioning rear wiper can significantly reduce visibility in wet or snowy conditions, posing a safety hazard. | Promptly addressing the B1839 code is important for maintaining safe driving conditions. |
| Cost of Repair | The cost of repair can vary depending on the cause of the problem. Fuse replacement is the cheapest, while BCM replacement is the most expensive. | Obtaining estimates from multiple repair shops can help you find the best price. |
| Preventative Measures | Regularly inspect and clean wiring and connectors, especially in areas prone to moisture. | Applying dielectric grease to connectors can help prevent corrosion. |
Detailed Explanations
Definition: B1839 specifically points to an electrical fault within the rear wiper motor's circuit. This means the control module isn't receiving the expected signals, preventing the motor from operating normally. It's crucial to address this as it directly impacts visibility during adverse weather conditions.
Symptoms: The most obvious symptom is a rear wiper that doesn't work at all. Other symptoms include intermittent operation (working sometimes but not always), the wiper stopping abruptly mid-cycle, a blown fuse related to the rear wiper, or a warning light illuminating on the dashboard (though this is less common for this specific code).
Possible Causes: The root cause can vary. A faulty rear wiper motor itself is a common culprit. Damaged wiring or connectors, often due to physical damage or corrosion, can also disrupt the circuit. A blown fuse, a faulty rear wiper switch, or, in rarer cases, a malfunctioning Body Control Module (BCM) can also trigger the B1839 code.
Diagnostic Steps: Start with a visual inspection of the wiring and connectors associated with the rear wiper motor. Check for any signs of damage, corrosion, or loose connections. Test the rear wiper motor directly with a power source to see if it functions. Check the fuse related to the rear wiper. Use a multimeter to check for continuity and voltage in the circuit. Finally, scan the BCM for any related trouble codes that might provide further clues.
Common Repair Solutions: The repair will depend on the identified cause. Replacing the rear wiper motor is often necessary if it's faulty. Repairing or replacing damaged wiring or connectors is essential for restoring the circuit. Cleaning corroded connections can resolve many intermittent issues. A blown fuse should be replaced. If the rear wiper switch is faulty, it should be replaced. In rare instances, the BCM might need reprogramming or replacement.
Related Codes: While B1839 specifically targets the rear wiper motor circuit, other codes can provide additional context. B1838 (Rear Wiper Motor Relay Circuit Malfunction) indicates a problem with the relay controlling the motor. Other "B" codes related to the body control module or "U" codes related to communication errors might suggest a more complex electrical issue affecting multiple systems.
Tools Required: A multimeter is essential for testing continuity and voltage. A diagnostic scan tool is needed to read and clear trouble codes. Wiring diagrams are invaluable for tracing the circuit. Basic hand tools like screwdrivers, pliers, and wire strippers/crimpers are also necessary. Connector cleaner can help remove corrosion.
Safety Precautions: Always disconnect the negative battery terminal before working on the electrical system to prevent accidental shorts and potential injury. Wear safety glasses to protect your eyes from debris. Exercise caution when working with electrical components and consult the vehicle's service manual for specific procedures.
Fuse Location: The fuse for the rear wiper motor is typically located in either the interior fuse box (often under the dashboard) or the engine compartment fuse box. Refer to the vehicle's owner's manual or service manual to find the exact location and amperage rating of the fuse.
Wiring Diagram Importance: A wiring diagram is crucial for tracing the rear wiper motor circuit, identifying components, and verifying wiring connections. It helps you understand the flow of electricity and pinpoint the exact location of the fault.
BCM Involvement: The Body Control Module (BCM) controls the operation of the rear wiper motor and monitors the circuit for faults. If the BCM is malfunctioning, it can incorrectly trigger the B1839 code, even if the motor and wiring are fine.
Corrosion Issues: Corrosion on wiring and connectors is a common cause of electrical problems, including the B1839 code. Corrosion creates resistance in the circuit, hindering the flow of electricity and causing the motor to malfunction.
Motor Testing: You can test the rear wiper motor directly by disconnecting it from the vehicle's wiring harness and applying 12 volts directly to the motor terminals. If the motor runs, it's likely that the problem lies elsewhere in the circuit. If it doesn't run, the motor is likely faulty.
Switch Testing: Use a multimeter to test the rear wiper switch for continuity in the different switch positions. This will verify that the switch is functioning correctly and sending the appropriate signals to the BCM.
Intermittent Problems: Intermittent B1839 codes can be particularly challenging to diagnose. These often indicate loose connections, chafed wires, or water intrusion. Careful and thorough inspection is key to finding the source of the problem.
DIY vs. Professional: Simple repairs, such as replacing a blown fuse or cleaning corroded connections, can often be done by a DIY enthusiast. However, more complex repairs, such as replacing the motor or diagnosing a faulty BCM, may require the expertise of a professional mechanic.
Vehicle-Specific Information: The exact location of components and wiring diagrams can vary significantly depending on the vehicle's make and model. Always consult the vehicle's service manual for specific information related to your vehicle.
Impact on Safety: A non-functioning rear wiper can significantly reduce visibility in wet or snowy conditions, posing a safety hazard to the driver and other road users.
Cost of Repair: The cost of repair will depend on the cause of the problem. Replacing a fuse is the cheapest, while replacing the BCM is the most expensive.
Preventative Measures: Regularly inspect and clean wiring and connectors, especially in areas that are prone to moisture. Applying dielectric grease to connectors can help prevent corrosion and ensure reliable electrical connections.
Frequently Asked Questions
What does the B1839 code mean? It indicates a problem in the rear wiper motor circuit, preventing proper operation.
What are the symptoms of a B1839 code? The most common symptom is a rear wiper that doesn't work.
What could cause the B1839 code? Possible causes include a faulty motor, damaged wiring, a blown fuse, or a bad BCM.
Can I fix the B1839 code myself? Simple fixes like fuse replacement can be DIY, but complex repairs often require a professional.
How important is it to fix the B1839 code? It's important for safety, as a working rear wiper improves visibility in bad weather.
Conclusion
The B1839 code signifies a fault in the rear wiper motor circuit, often resulting in a non-functioning rear wiper. Thorough diagnosis and repair are essential for restoring visibility and ensuring safe driving conditions.