B1459 Wiper Washer Pump Motor Relay Coil Circuit Open

Introduction

The B1459 diagnostic trouble code (DTC) indicates an open circuit in the relay coil circuit that controls the wiper washer pump motor. This means the vehicle's computer (ECU) isn't receiving the expected electrical signal from the relay, preventing the washer pump from activating. Understanding this code and its potential causes is crucial for effectively diagnosing and resolving the issue, ensuring proper windshield cleaning and safe driving conditions.

B1459 Code Details

Detailed Explanations

Definition: Wiper Washer Pump Motor Relay Coil Circuit Open

This code specifically points to a problem in the electrical circuit that powers the coil of the wiper washer pump relay. Relays act as electrically controlled switches. The coil, when energized, creates a magnetic field that pulls the relay's contacts together, completing the circuit to the washer pump motor. An "open circuit" means a break in this electrical path, preventing the coil from energizing and the relay from activating the pump.

Possible Causes

• Faulty Wiper Washer Pump Relay: The relay itself can fail internally. The coil winding can break, preventing it from creating a magnetic field. Internal contacts might also be corroded or damaged, preventing proper activation.

• Open Circuit in Wiring to Relay Coil: This is a break in the wire that carries power or ground to the relay coil. This break can be caused by physical damage, corrosion, or a loose connection. This is perhaps the most common cause.

• Corroded or Loose Relay Connector: The electrical connector that plugs into the relay can become corroded due to moisture and environmental factors. Corrosion can increase resistance in the circuit, preventing sufficient current flow to energize the relay coil. A loose connector can also interrupt the electrical path.

• Faulty Body Control Module (BCM): The BCM is a computer module that controls various electrical functions in the vehicle, including the wiper washer system. While less common, a malfunction within the BCM can prevent it from sending the signal to activate the washer pump relay.

• Blown Fuse (related to the washer system): A blown fuse in the washer pump circuit will prevent the relay coil from receiving power. This is often the easiest and first thing to check.

Symptoms

• Washer pump inoperative: This is the primary symptom. When you activate the washer pump (usually by pulling or pushing the wiper stalk), no washer fluid is sprayed onto the windshield.

• No washer fluid sprayed when activated: No sound of the pump operating will be heard.

• Check Engine Light (CEL) illuminated (possibly): Some vehicles may illuminate the CEL when the B1459 code is stored. However, this is not always the case.

• Other electrical issues (depending on vehicle design): In some cases, the washer pump circuit might be tied to other electrical functions. If the open circuit is causing a significant voltage drop or short, it might affect other systems.

Diagnostic Steps

1. Inspect Fuse: Locate the fuse for the wiper washer system (refer to the owner's manual or a wiring diagram). Check the fuse for continuity using a multimeter. If the fuse is blown, replace it with a fuse of the correct amperage rating. If the fuse blows again immediately, there is likely a short circuit in the system.

2. Check Relay: Locate the wiper washer pump relay (refer to the owner's manual or a wiring diagram). There are several ways to test the relay:

   • Swap with a known good relay: If you have a relay of the same type used for another function in the vehicle (e.g., horn, lights), swap it with the washer pump relay. If the washer pump now works, the original relay is faulty.
   • Test the relay using a multimeter: You can test the relay coil's resistance. Disconnect the relay and use a multimeter to measure the resistance between the coil terminals. A reading of infinity or zero ohms indicates a faulty coil. Also, you can apply 12V to the coil terminals and listen for a "click" sound, indicating the relay is switching.

3. Inspect Wiring and Connectors:

   • Visually inspect the wiring harness and connectors leading to the relay and the washer pump motor for any signs of damage, corrosion, or loose connections.
   • Pay close attention to areas where the wiring might be exposed to chafing or rubbing.
   • Clean any corroded terminals with a wire brush or electrical contact cleaner.
   • Ensure that all connectors are securely plugged in.

4. Test Relay Coil Circuit:

   • Using a multimeter, check for voltage at the relay coil terminals when the washer pump is activated. You should see approximately battery voltage (12V). If there is no voltage, there is an open circuit in the wiring leading to the relay or a problem with the BCM output.
   • Check the ground circuit for the relay coil. Ensure there is a good ground connection.

5. Test BCM Output: If you suspect a problem with the BCM, you will need a scan tool that can access the BCM's output signals. Check if the BCM is sending the correct signal to activate the washer pump relay when the washer pump is activated.

6. Consult Vehicle-Specific Wiring Diagrams: Wiring diagrams are essential for accurate diagnosis. They show the exact wiring paths, connector locations, and component locations for the washer pump circuit in your specific vehicle.

Common Fixes

• Replace faulty wiper washer pump relay: If the relay is found to be faulty, replace it with a new relay of the correct type.

• Repair or replace damaged wiring: Repair any damaged wiring by splicing in new wire and using proper crimping techniques. Protect the repaired wiring with electrical tape or heat shrink tubing. If the wiring is severely damaged, it may be necessary to replace the entire wiring harness section.

• Clean or replace corroded connectors: Clean corroded connectors with a wire brush or electrical contact cleaner. If the corrosion is severe, replace the connector. Apply dielectric grease to the connector terminals to prevent future corrosion.

• Replace blown fuse: Replace the blown fuse with a fuse of the correct amperage rating. If the fuse blows again immediately, there is likely a short circuit in the system that needs to be located and repaired.

• Replace faulty BCM (rare): Replacing the BCM should be the last resort, as it is a complex and expensive repair. Before replacing the BCM, ensure that all other possible causes have been ruled out. The BCM may also require programming after replacement.

Frequently Asked Questions

Q: What does the B1459 code mean? A: It means there's an open circuit in the relay coil circuit that controls your windshield washer pump. This prevents the pump from activating.

Q: Can I still drive with the B1459 code? A: Yes, but it's not recommended. You won't be able to clean your windshield, which can be a safety hazard in inclement weather.

Q: Is the B1459 code serious? A: While not immediately disabling, it affects visibility and safety, especially during rain, snow, or when the windshield is dirty.

Q: How do I fix the B1459 code? A: Check the fuse, relay, wiring, and connectors for the washer pump system. Replace any faulty components.

Q: Can a bad relay cause the B1459 code? A: Yes, a faulty or corroded relay is a common cause of the B1459 code.

Conclusion

The B1459 code indicates a problem with the electrical circuit controlling the wiper washer pump, directly impacting driving visibility and safety. Thorough diagnosis, starting with simple checks like fuses and relays, is key to resolving the issue efficiently and restoring proper windshield cleaning functionality.