Introduction:
The diagnostic trouble code (DTC) B1591 indicates a fault within the power mirror system of a vehicle, specifically related to the vertical position sensor of one of the mirrors. This error signifies that the vehicle's computer (ECU/BCM) has detected an abnormal signal from the vertical position sensor, suggesting it's either reporting a value outside the acceptable range or is completely disconnected (open circuit). Understanding the causes and troubleshooting steps for B1591 is crucial for restoring proper mirror functionality and ensuring safe driving.
Comprehensive Table: B1591 - Mirror Vert. Pos Sensor-Out of Range/Open
| Category | Description | | Category | Description | Possible Symptoms | | Definition | B1591 is a Diagnostic Trouble Code (DTC) indicating a fault in the vehicle's power mirror system. It specifically points to an issue with the vertical position sensor signal for one of the side mirrors. The signal is either out of range (too high or too low) or completely absent (open circuit). | Mirror does not adjust vertically, Mirror moves erratically or not at all, Error message on dashboard or scan tool, Difficulty in setting mirror position. | | Affected System | Power Mirror System | N/A | | Possible Causes | Damaged vertical position sensor, Faulty wiring or connectors (corrosion, loose connections, breaks), Open or short circuit in the sensor circuit, Internal failure within the power mirror motor assembly, Faulty Body Control Module (BCM) or other related control module, Incorrect sensor calibration, Physical damage to the mirror assembly. | N/A | | Diagnostic Steps | Scan the vehicle's computer system for DTCs, Inspect the wiring and connectors leading to the mirror and sensor, Check the sensor's resistance and voltage output with a multimeter, Test the power mirror motor functionality, Verify the sensor's calibration, Inspect the mirror assembly for physical damage, Check for continuity in the wiring harness, Compare sensor readings to specifications. | N/A | | Common Solutions | Replacing the faulty vertical position sensor, Repairing or replacing damaged wiring or connectors, Replacing the entire power mirror motor assembly, Recalibrating the sensor, Replacing the faulty control module (BCM), Cleaning corroded connectors, Repairing any physical damage to the mirror assembly. | N/A | | Tools Required | OBD-II scanner, Multimeter, Wiring diagram, Basic hand tools (screwdrivers, pliers, etc.), Connector cleaner, Replacement parts (sensor, wiring, motor). | N/A | | Severity | Moderate. While not directly impacting the vehicle's drivability, malfunctioning mirrors can significantly reduce visibility and increase the risk of accidents. ிலான\ | Complexity | Moderate. Requires a systematic approach to diagnosis and troubleshooting. | | Safety Considerations | Always disconnect the vehicle's battery before working on electrical components. Use caution when handling wiring and connectors to avoid damage. Consult a qualified technician if you are not comfortable performing these repairs yourself. | N/A |
Detailed Explanations:
Definition: The B1591 DTC specifically points to an error in the signal received from the vertical position sensor within the power mirror assembly. The Electronic Control Unit (ECU) or Body Control Module (BCM) monitors this sensor to determine the mirror's vertical orientation. When the sensor output falls outside the pre-defined acceptable range (either too high or too low) or is completely absent (indicating an open circuit), the B1591 code is triggered. This code is important because it means the mirror's vertical adjustment is not functioning as intended, which can impair visibility.
Affected System: The power mirror system is responsible for allowing the driver to adjust the position of the side mirrors electronically. This system includes the mirror adjustment switch, wiring, the mirror motor assembly itself, and the Body Control Module (BCM) or other relevant control module that controls the mirror functions. The vertical position sensor is a component within the mirror motor assembly that provides feedback to the BCM about the mirror's current vertical angle. The system's proper functioning is crucial for driver safety and comfort.
Possible Causes: Several factors can contribute to the B1591 code. A damaged vertical position sensor is a primary suspect, as the sensor itself might be faulty. Faulty wiring and connectors are also common culprits. Corrosion, loose connections, or breaks in the wiring harness can disrupt the signal from the sensor to the BCM. An open or short circuit within the sensor circuit will also cause the code. In some cases, the power mirror motor assembly itself may have an internal failure. A faulty Body Control Module (BCM), although less common, could also be the source of the problem. Furthermore, incorrect sensor calibration can lead to inaccurate readings, triggering the code. Finally, physical damage to the mirror assembly can sometimes affect the sensor's operation.
Diagnostic Steps: A methodical approach is essential for diagnosing the root cause of the B1591 code. Start by using an OBD-II scanner to confirm the presence of the B1591 code and check for any other related DTCs. Next, perform a visual inspection of the wiring and connectors leading to the affected mirror and sensor. Look for any signs of damage, corrosion, or loose connections. Use a multimeter to check the sensor's resistance and voltage output. Compare these readings to the specifications provided in the vehicle's service manual. Test the power mirror motor's functionality to ensure it can move the mirror in all directions. Verify the sensor's calibration using a scan tool if the vehicle supports it. Inspect the mirror assembly for any physical damage. Check for continuity in the wiring harness to rule out any open circuits.
Common Solutions: The solution to a B1591 code depends on the underlying cause. Replacing the faulty vertical position sensor is often necessary if the sensor itself is defective. Repairing or replacing damaged wiring or connectors is crucial to ensure a proper signal transmission. In some cases, replacing the entire power mirror motor assembly might be the most effective solution, especially if the motor itself is failing or if the sensor is integrated into the motor assembly. Recalibrating the sensor may resolve the issue if the sensor is simply miscalibrated. If the BCM is faulty, replacing the faulty control module will be required. Cleaning corroded connectors with a suitable electrical contact cleaner can restore proper connections. And, of course, repairing any physical damage to the mirror assembly is essential.
Tools Required: To properly diagnose and repair the B1591 code, you'll need a few essential tools. An OBD-II scanner is necessary to read and clear DTCs. A multimeter is crucial for testing voltage, resistance, and continuity. A wiring diagram for the vehicle's power mirror system is invaluable for tracing circuits and identifying connector locations. Basic hand tools like screwdrivers, pliers, and wire strippers are needed for accessing and working on the wiring and connectors. Connector cleaner can help remove corrosion from electrical connections. Finally, be prepared to have replacement parts on hand, such as a new sensor, wiring harness, or motor assembly.
Severity: While a B1591 code doesn't typically prevent the vehicle from being driven, it's considered a moderate severity issue. The primary concern is the reduced visibility caused by a malfunctioning mirror. This can make it difficult to see vehicles and objects in the blind spots, increasing the risk of accidents, especially when changing lanes or making turns. Therefore, it's important to address the B1591 code as soon as possible to ensure safe driving conditions.
Frequently Asked Questions:
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