B1621 – Wiper Rear Low Limit Input Circuit Short To Battery
The ODBII code B1621 indicates a malfunction in the rear wiper system, specifically that the low limit input circuit is shorted to the battery, which means there is an electrical short causing the circuit to receive constant power.
The severity of ODBII code B1621 is moderate.
Common Causes For: B1620 Wiper Rear Low Limit Input Circuit Open
- Shorted wiring or connectors
- Faulty rear wiper motor
- Malfunctioning wiper switch
- Corroded or damaged electrical connections
- Failed body control module (BCM)
- Ground circuit issues
Common misdiagnosis for B1621 Wiper Rear Low Limit Input Circuit Short To Battery
- Faulty rear wiper motor
- Damaged wiring or connectors
- Malfunctioning body control module (BCM)
- Incorrectly installed or defective wiper switch
- Short circuit in the wiring harness
- Faulty ground connection
- Issues with the main fuse or relay for the wiper system
Common Troubleshooting Steps
The OBD-II code B1621 indicates a problem with the rear wiper low limit input circuit, specifically a short to battery. This code is often associated with issues in the rear wiper system of a vehicle. Here are some common troubleshooting steps to diagnose and resolve the issue:
- Visual Inspection: **Wiring and Connectors: Inspect the wiring harness and connectors related to the rear wiper motor and the low limit switch. Look for any signs of damage, fraying, or corrosion.
- **Ground Connections: Ensure that all ground connections are secure and free of corrosion.
- Check the Rear Wiper Motor: **Functionality: Test the rear wiper motor to ensure it operates correctly. If the motor is faulty, it may cause the circuit to short.
- **Resistance Test: Measure the resistance of the motor windings. If the resistance is too low, the motor may be shorted internally.
- Inspect the Low Limit Switch: **Functionality: Check the rear wiper low limit switch for proper operation. This switch is responsible for signaling the wiper control module when the wiper is in the “home” position.
- **Continuity Test: Use a multimeter to test for continuity in the switch. If it is stuck closed or open, it may need to be replaced.
- Check for Short Circuits: **Wiring Inspection: Look for any areas where the wiring may be pinched, frayed, or in contact with metal surfaces that could cause a short to battery.
- **Multimeter Testing: Use a multimeter to check for continuity between the low limit input circuit and battery voltage. If there is continuity, it indicates a short.
- Scan for Additional Codes: **OBD-II Scanner: Use an OBD-II scanner to check for any additional trouble codes that may provide more context to the issue. Addressing related codes may resolve the B1621 code.
- Check the Wiper Control Module: **Module Functionality: If all other components check out, the issue may lie within the wiper control module itself. Inspect for any signs of damage or failure.
- **Reprogramming/Resetting: In some cases, reprogramming or resetting the module may be necessary.
- Clear Codes and Test Drive: After performing the necessary repairs, clear the trouble codes using the OBD-II scanner and take the vehicle for a test drive to see if the code returns.
- Consult Service Manual: If the issue persists, consult the vehicle’s service manual for specific wiring diagrams and troubleshooting procedures related to the rear wiper system.
- Seek Professional Help: If you are unable to diagnose or fix the issue, consider seeking assistance from a qualified mechanic or automotive technician. By following these steps, you should be able to identify and resolve the issue associated with the B1621 code.