Introduction:

The B1479 diagnostic trouble code (DTC) indicates a fault within the wiper washer fluid level sensor circuit. This sensor is crucial for alerting the driver when the washer fluid reservoir is low, preventing unexpected depletion during driving, which can severely impair visibility. A malfunctioning sensor can lead to inaccurate warnings or, conversely, a failure to warn when the fluid is dangerously low, posing a safety risk.

B1479 Wiper Washer Fluid Level Sensor Circuit Failure: A Comprehensive Guide

| Aspect | Description | Possible Causes to be able to deliver the correct information based on the sensor.

Location: Typically found attached to the side or bottom of the windshield washer fluid reservoir, often accessible from under the hood.

Function: The sensor monitors the washer fluid level, sending a signal to the vehicle's computer (ECU) to illuminate a warning light on the dashboard when the fluid is low.

Symptoms of a B1479 Code:

  • Washer fluid warning light illuminated constantly: This indicates a possible fault in the circuit, even when the washer fluid level is adequate.
  • Washer fluid warning light not illuminating when fluid is low: This is a more dangerous scenario, as the driver may not be aware that the fluid needs to be refilled.
  • Intermittent washer fluid warning light: The light may flicker or illuminate sporadically, which can be caused by a loose connection or a faulty sensor.
  • No visible issues, but the code is present: The sensor might be sending an incorrect signal that doesn't match the actual fluid level, triggering the code.
  • Inability to use the windshield washer system: In some cases, the vehicle's computer may disable the windshield washer system to prevent damage or further issues if it detects a problem with the sensor circuit. This is less common but possible.

Causes of B1479 Code:

  • Faulty Washer Fluid Level Sensor: The sensor itself may be defective and unable to accurately measure the fluid level. This is a very common cause.
  • Open or Shorted Wiring: The wiring connecting the sensor to the ECU may be damaged, causing an open circuit (break in the wire) or a short circuit (wire touching ground or another wire).
  • Corroded Connectors: Corrosion on the sensor's connector or the connector at the ECU can disrupt the electrical signal.
  • High Resistance in the Circuit: Resistance in the wiring or connectors can affect the signal sent to the ECU.
  • Faulty ECU: In rare cases, the ECU itself may be malfunctioning and misinterpreting the signal from the sensor.
  • Damaged Washer Fluid Reservoir: A cracked or damaged reservoir can leak fluid and affect the sensor's reading.
  • Incorrect Fluid Type: Although less common, using the wrong type of washer fluid (e.g., water instead of a proper fluid) can sometimes affect the sensor's performance, particularly if the sensor relies on conductivity.
  • Rodent Damage: Wires can be chewed on by rodents, causing shorts or breaks in the circuit.
  • Aftermarket Accessories: Improperly installed aftermarket accessories can interfere with the sensor circuit.
  • Loose ground connection: A loose ground connection for the sensor or the ECU can cause intermittent or incorrect readings.

Troubleshooting Steps:

  1. Visual Inspection:
    • Check the Washer Fluid Level: Ensure the reservoir is filled to the appropriate level.
    • Inspect the Sensor: Look for any visible damage to the sensor itself, such as cracks or broken parts.
    • Inspect the Wiring: Carefully examine the wiring harness and connectors leading to the sensor for any signs of damage, corrosion, or loose connections. Pay close attention to the area where the wiring is routed near the reservoir and other components, as this is where damage is most likely to occur.
  2. Electrical Testing:
    • Check for Voltage: Use a multimeter to check for voltage at the sensor connector. Refer to the vehicle's wiring diagram for the correct voltage readings.
    • Check for Ground: Verify that the sensor has a good ground connection.
    • Check for Continuity: Use a multimeter to check the continuity of the wiring between the sensor and the ECU. This will help identify any open circuits.
    • Check Resistance: Measure the resistance of the sensor itself. Compare the reading to the manufacturer's specifications. High resistance can indicate a faulty sensor.
  3. Component Testing:
    • Sensor Functionality Test: Some sensors can be tested by manually changing the fluid level and observing the signal output.
    • ECU Testing: Testing the ECU typically requires specialized equipment and expertise. It's usually performed by a qualified technician.
  4. Scan Tool Diagnostics:
    • Clear the Code: After performing repairs, clear the B1479 code using a scan tool.
    • Monitor Sensor Data: Use the scan tool to monitor the sensor's data stream to see if the signal is changing appropriately.
    • Perform Actuator Tests: Some scan tools can perform actuator tests to activate the washer fluid pump and see if the sensor responds correctly.

Tools Required for Diagnosis and Repair:

  • OBD-II Scan Tool: To read and clear diagnostic trouble codes.
  • Multimeter: To measure voltage, resistance, and continuity.
  • Wiring Diagram: To understand the sensor circuit and identify the correct wires for testing.
  • Wire Strippers and Crimpers: For repairing damaged wiring.
  • Connectors and Terminals: To replace damaged connectors.
  • Socket Set and Wrenches: To remove and install the sensor.
  • Pry Bar or Screwdriver: To access the sensor.
  • Electrical Contact Cleaner: To clean corroded connectors.
  • Test Light: To check for power and ground.

Common Mistakes to Avoid:

  • Replacing the sensor without proper diagnosis: Always perform thorough troubleshooting before replacing any parts.
  • Ignoring wiring and connector issues: These are often the root cause of the problem.
  • Using the wrong replacement parts: Ensure that the replacement sensor and connectors are compatible with the vehicle.
  • Failing to clear the code after repairs: Clearing the code is necessary to reset the system and ensure that the problem is resolved.
  • Overlooking other related codes: Address any other diagnostic trouble codes that may be present, as they could be contributing to the B1479 code.

Potential Repair Solutions:

  • Replacing the Washer Fluid Level Sensor: If the sensor is faulty, replacing it is the most common solution.
  • Repairing Damaged Wiring: Repair any damaged wiring by splicing in new wires or replacing the entire wiring harness section.
  • Cleaning or Replacing Corroded Connectors: Clean corroded connectors with electrical contact cleaner. If the corrosion is severe, replace the connectors.
  • Tightening Loose Connections: Ensure that all connections are tight and secure.
  • Replacing the ECU: In rare cases, replacing the ECU may be necessary if it is malfunctioning. This should only be done after all other possible causes have been ruled out.
  • Repairing or Replacing the Washer Fluid Reservoir: If the reservoir is cracked or damaged, repair it with epoxy or replace it.
  • Checking and Repairing Ground Connections: Ensure all ground connections related to the sensor circuit and ECU are clean, tight, and free from corrosion.

Detailed Explanations

Faulty Washer Fluid Level Sensor: The sensor contains a mechanism, often a float or conductivity probe, that detects the fluid level. Over time, this mechanism can fail due to wear and tear, corrosion, or contamination, leading to inaccurate readings.

Open or Shorted Wiring: An open circuit occurs when a wire is broken, preventing the electrical signal from flowing. A short circuit occurs when a wire comes into contact with ground or another wire, creating an unintended path for the electrical current. These wiring issues are often caused by physical damage, such as rubbing against other components or being pinched.

Corroded Connectors: Corrosion forms on electrical connectors due to exposure to moisture and contaminants. This corrosion increases resistance in the circuit, hindering the flow of electrical current and disrupting the signal sent to the ECU.

High Resistance in the Circuit: High resistance can be caused by corroded connectors, damaged wiring, or a faulty sensor. It reduces the amount of current flowing through the circuit, which can affect the signal sent to the ECU.

Faulty ECU: The ECU (Engine Control Unit) is the vehicle's computer that receives and processes signals from various sensors, including the washer fluid level sensor. A faulty ECU may misinterpret the sensor's signal or fail to recognize it altogether. However, ECU failure is a less common cause compared to sensor or wiring issues.

Damaged Washer Fluid Reservoir: A crack in the reservoir can lead to fluid leaks which, in turn, lead to the sensor giving an incorrect reading.

Incorrect Fluid Type: While not as common, using plain water instead of proper washer fluid can affect the sensor's readings, especially if the sensor relies on the fluid's conductivity.

Rodent Damage: Rodents can chew on the car's wiring harness, which can cause shorted, open, or damaged wires, thus causing the B1479 code.

Aftermarket Accessories: Improper installation of aftermarket accessories, such as lights or audio systems, can sometimes interfere with the wiring related to the washer fluid sensor circuit.

Loose ground connection: A loose ground connection results in an incomplete circuit and can cause a variety of electrical problems.

Frequently Asked Questions

  • What does the B1479 code mean? It signifies a problem with the electrical circuit of the wiper washer fluid level sensor.

  • Can I drive with the B1479 code? Yes, but it's not recommended. While the car will function, you won't receive a low washer fluid warning, which can be a safety hazard.

  • Is the B1479 code serious? It's not critical, but it's a safety concern. A functioning washer fluid system is essential for visibility in adverse weather.

  • How much does it cost to fix a B1479 code? The cost depends on the cause. Replacing the sensor is typically inexpensive, while repairing wiring or replacing the ECU can be more costly.

  • Can I fix the B1479 code myself? If you have basic mechanical and electrical skills, you can diagnose and repair the issue yourself. However, if you're not comfortable working with electrical systems, it's best to take it to a professional.

  • What is the location of the Washer Fluid Level Sensor? It is located on the side or bottom of the windshield washer fluid reservoir.

Conclusion

The B1479 code indicates a problem with the wiper washer fluid level sensor circuit, potentially compromising your ability to maintain clear visibility while driving. By systematically troubleshooting the sensor, wiring, and connectors, you can identify the root cause and restore proper functionality to the washer fluid warning system.