B1240 – OBD-II DTC

OBD-II DTC B1240 – Wiper Washer Rear Pump Relay Circuit Failure

DTC B1240 meaning

DTC B1240 refers to a fault in the rear wiper washer pump relay circuit. This diagnostic trouble code indicates that the vehicle’s onboard diagnostic system has detected an issue with the electrical circuit that controls the rear wiper washer pump. The relay is responsible for supplying power to the pump, and a failure in this circuit can prevent the rear washer from functioning properly.

DTC B1240 symptoms

Common symptoms associated with DTC B1240 may include:

• Rear wiper washer not functioning
• Inoperative rear wiper
• Warning lights on the dashboard
• Intermittent operation of the rear washer

DTC B1240 causes

Several factors can lead to the occurrence of DTC B1240, including:

• Faulty rear wiper washer pump relay
• Damaged wiring or connectors in the relay circuit
• Short circuits or open circuits in the electrical system
• Defective rear wiper washer pump
• Issues with the vehicle’s body control module (BCM)

DTC B1240 seriousness

The seriousness of DTC B1240 can vary depending on the vehicle’s use and the conditions in which it operates. While it may not affect the vehicle’s overall drivability, it can hinder visibility during inclement weather if the rear washer is inoperative. Therefore, it is advisable to address this issue promptly to ensure safe driving conditions.

How to diagnose DTC B1240

To diagnose DTC B1240, follow these steps:

1. Use an OBD-II scanner to confirm the presence of DTC B1240.
2. Inspect the rear wiper washer pump relay for any visible damage.
3. Check the wiring and connectors for signs of wear, corrosion, or disconnection.
4. Test the relay using a multimeter to ensure it is functioning correctly.
5. Examine the rear wiper washer pump for proper operation.
6. Check the body control module for any related fault codes.

How to fix DTC B1240 step-by-step instructions

To fix DTC B1240, follow these step-by-step instructions:

1. Replace the faulty rear wiper washer pump relay if it is defective.
2. Repair or replace any damaged wiring or connectors in the relay circuit.
3. Test the rear wiper washer pump and replace it if it is not functioning.
4. Clear any fault codes from the vehicle’s computer using an OBD-II scanner.
5. Perform a final test to ensure the rear wiper washer system is operational.

How to erase DTC B1240

To erase DTC B1240, follow these steps:

1. Connect an OBD-II scanner to the vehicle’s diagnostic port.
2. Turn on the ignition without starting the engine.
3. Navigate to the “Erase Codes” or “Clear Codes” option on the scanner.
4. Confirm the action to clear the DTC from the vehicle’s memory.
5. Disconnect the scanner and start the vehicle to verify that the code does not reappear.

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