Introduction

The B1822 diagnostic trouble code (DTC) indicates a fault within the rear park assist system related to the wiper motor signal. This code often suggests an issue with the electrical circuit connecting the wiper motor and the park assist module. Understanding the causes, symptoms, and troubleshooting steps for this code is crucial for maintaining the functionality of both the rear wiper and the park assist systems, ensuring driver safety and convenience.

Table: B1822 Wiper Rear Park Sense Input Circuit Failure

Detailed Explanations

Code Definition: B1822 is a diagnostic trouble code (DTC) indicating a fault in the "Wiper Rear Park Sense Input Circuit." This generally means the vehicle's computer (specifically, the park assist module) is not receiving the expected signal from the rear wiper motor circuit.

System Affected: The primary systems affected are the Rear Park Assist System and the Rear Wiper System. The code indicates a communication problem between these two systems, potentially leading to malfunctions in either or both.

Possible Causes:

• Short to ground in wiring harness: This occurs when the wiring insulation is damaged, causing the wire to make contact with the vehicle's chassis or other grounded metal components.
• Open circuit in wiring harness: This happens when a wire is broken or disconnected, preventing the signal from reaching its destination.
• Damaged or corroded connectors: Corrosion or physical damage to the connectors can disrupt the electrical connection between the components.
• Faulty rear wiper motor: A malfunctioning wiper motor may not send the correct signal to the park assist module.
• Defective park assist module: The park assist module itself could be faulty, unable to correctly interpret the signal from the wiper motor.
• CAN bus communication issues (less common): The Controller Area Network (CAN) bus is a communication network within the vehicle. Issues with the CAN bus can sometimes interfere with the signal transmission.
• Incorrect wiper motor installation (if recently replaced): If the wiper motor was recently replaced, improper installation could cause signal issues.
• Interference from aftermarket electronics: Aftermarket accessories or modifications can sometimes interfere with the vehicle's electrical system.

Related Components:

• Rear wiper motor: The motor that powers the rear wiper blade.
• Park assist module (PAM): The control module responsible for processing park assist sensor data and providing alerts.
• Wiring harness: The network of wires that connect the various components.
• Connectors: The electrical connectors that join the wires to the components.
• Fuses: Protective devices that prevent overcurrent situations.
• Relays: Electrically operated switches that control the power to certain circuits.
• Body Control Module (BCM): A central control unit that manages various body functions, including wiper control.
• CAN bus network: The communication network within the vehicle.

Diagnostic Tools:

• OBD-II scanner: Used to retrieve diagnostic trouble codes (DTCs).
• Multimeter: Used to measure voltage, resistance, and current in electrical circuits.
• Wiring diagram: A schematic diagram showing the wiring connections between the components.
• Test light: A simple tool to check for the presence of voltage in a circuit.
• Oscilloscope (for advanced diagnostics): Used to visualize electrical signals over time.

Troubleshooting Steps:

• Visual inspection of wiring and connectors: Look for any signs of damage, corrosion, or loose connections.
• Testing wiper motor operation: Ensure the rear wiper motor is functioning correctly.
• Checking for voltage and ground at the PAM: Verify that the PAM is receiving power and ground.
• Testing continuity of wiring between wiper motor and PAM: Ensure there are no breaks in the wiring between the wiper motor and the PAM.
• Testing the resistance of the wiper motor: Check the resistance of the wiper motor windings to identify any internal faults.
• Scan for other DTCs: Check for other DTCs that may be related to the B1822 code.
• Inspecting fuses and relays: Check the fuses and relays associated with the wiper motor and park assist system.
• Testing the park assist sensors: Ensure the park assist sensors are functioning correctly.
• Testing the PAM using a scan tool: Use a scan tool to perform diagnostic tests on the PAM.

Common Symptoms:

• Rear park assist not working: The park assist system may not function correctly.
• Rear wiper not working: The rear wiper motor may not operate.
• Intermittent operation: Both the park assist and wiper systems may work intermittently.
• False alarms: The park assist system may generate false alarms even when there are no obstacles.
• Service park assist light on: The "Service Park Assist" warning light may illuminate on the dashboard.

Severity Level: Medium - While not immediately critical to the vehicle's operation, it impacts safety and convenience features, potentially leading to accidents while reversing.

Repair Costs: Repair costs are highly variable. A simple wiring repair might cost $50-$150, while replacing a faulty PAM or wiper motor can cost $200-$500 or more, including labor.

Preventative Measures:

• Regular vehicle maintenance: Follow the manufacturer's recommended maintenance schedule.
• Inspecting wiring and connectors for damage: Periodically inspect the wiring and connectors for any signs of damage or corrosion.
• Protecting wiring from water and debris: Keep the wiring protected from water and debris.
• Avoiding aftermarket electronic modifications that may interfere with the vehicle's electrical system: Be cautious when installing aftermarket electronics and ensure they are compatible with the vehicle's electrical system.

Wiring Diagram Location: Vehicle-specific repair manuals (e.g., Haynes, Chilton) or online databases (e.g., Alldata, Mitchell OnDemand) contain detailed wiring diagrams.

Technical Service Bulletins (TSBs): Check for Technical Service Bulletins (TSBs) related to B1822 and the specific vehicle make and model. TSBs often provide specific diagnostic and repair procedures for known issues. You can usually find these on the NHTSA website or through a professional mechanic's database.

Common Vehicle Brands Affected: GM (Chevrolet, GMC, Cadillac, Buick), Ford, Chrysler, Dodge, Jeep (depending on model year and features). The specific models affected will vary depending on the year and equipment.

Park Sense System Operation: The park sense system uses ultrasonic sensors in the rear bumper to detect objects behind the vehicle when backing up. The PAM processes the signals from these sensors and provides audible and/or visual warnings to the driver when an object is detected. The signal from the rear wiper motor can be used by the PAM to adjust its sensitivity or operation, for example, to compensate for rain or snow on the rear window.

Wiper Motor Operation: The rear wiper motor is a small electric motor that drives the rear wiper blade. It is controlled by the driver through a switch, and typically has multiple speed settings. The motor contains a park switch that ensures the wiper blade stops in the correct position when turned off.

Circuit Description: The B1822 code specifically points to a problem with the input circuit to the PAM from the rear wiper motor. This input is usually a signal that indicates whether the rear wiper is currently active or not. The PAM might use this information to adjust the sensitivity of the park assist system. For example, if the wiper is on, the PAM might reduce the sensitivity to avoid false alarms caused by rain or snow. The circuit typically consists of a wire connecting the wiper motor to the PAM, along with any associated connectors and grounds.

Frequently Asked Questions

What does the B1822 code mean? It indicates a failure in the circuit that sends the rear wiper motor's status to the park assist module.

Can I still drive my car with the B1822 code? Yes, but your rear park assist and/or rear wiper might not function correctly.

What's the first thing I should check when I get this code? Visually inspect the wiring and connectors associated with the rear wiper motor and park assist module for damage or corrosion.

Is this a difficult problem to fix? It depends on the cause. Simple wiring repairs are relatively easy, but replacing a module can be more complex.

Can a bad fuse cause this code? Yes, a blown fuse in the wiper motor or park assist circuit can cause this code. Always check the fuses first.

How much will it cost to fix the B1822 code? Costs vary greatly. A simple wiring fix might be inexpensive, while replacing a module can be more costly.

Will this affect my car's performance? No, it won't affect the engine or transmission, but it will impact the functionality of your rear park assist and/or rear wiper.

Conclusion

The B1822 code signifies a malfunction in the communication between the rear wiper and park assist systems. Thorough diagnosis, starting with a visual inspection and progressing to component testing, is crucial for accurate identification and effective repair, ultimately restoring the functionality of both systems and ensuring driver safety.